To date, we have implemented two I/O usage models for persistent memory,
PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
userspace). This series adds a third, DAX-GUP, that allows DAX mappings
to be the target of direct-i/o. It allows userspace to coordinate
DMA/RDMA from/to persistent memory.
The implementation leverages the ZONE_DEVICE mm-zone that went into
4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
and dynamically mapped by a device driver. The pmem driver, after
mapping a persistent memory range into the system memmap via
devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
page-backed pmem-pfns via flags in the new pfn_t type.
The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
resulting pte(s) inserted into the process page tables with a new
_PAGE_DEVMAP flag. Later, when get_user_pages() is walking ptes it keys
off _PAGE_DEVMAP to pin the device hosting the page range active.
Finally, get_page() and put_page() are modified to take references
against the device driver established page mapping.
Finally, this need for "struct page" for persistent memory requires
memory capacity to store the memmap array. Given the memmap array for a
large pool of persistent may exhaust available DRAM introduce a
mechanism to allocate the memmap from persistent memory. The new
"struct vmem_altmap *" parameter to devm_memremap_pages() enables
arch_add_memory() to use reserved pmem capacity rather than the page
allocator.
This patch (of 18):
The core has developed a need for a "pfn_t" type [1]. Move the existing
pfn_t in KVM to kvm_pfn_t [2].
[1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html
[2]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002218.html
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Ground work for the new Power9 MMU from Aneesh Kumar K.V
- Optimise FP/VMX/VSX context switching from Anton Blanchard
- Various cleanups from Krzysztof Kozlowski, John Ogness, Rashmica Gupta,
Russell Currey, Gavin Shan, Daniel Axtens, Michael Neuling, Andrew Donnellan
- Allow wrapper to work on non-english system from Laurent Vivier
- Add rN aliases to the pt_regs_offset table from Rashmica Gupta
- Fix module autoload for rackmeter & axonram drivers from Luis de Bethencourt
- Include KVM guest test in all interrupt vectors from Paul Mackerras
- Fix DSCR inheritance over fork() from Anton Blanchard
- Make value-returning atomics & {cmp}xchg* & their atomic_ versions fully ordered from Boqun Feng
- Print MSR TM bits in oops messages from Michael Neuling
- Add TM signal return & invalid stack selftests from Michael Neuling
- Limit EPOW reset event warnings from Vipin K Parashar
- Remove the Cell QPACE code from Rashmica Gupta
- Append linux_banner to exception information in xmon from Rashmica Gupta
- Add selftest to check if VSRs are corrupted from Rashmica Gupta
- Remove broken GregorianDay() from Daniel Axtens
- Import Anton's context_switch2 benchmark into selftests from Michael Ellerman
- Add selftest script to test HMI functionality from Daniel Axtens
- Remove obsolete OPAL v2 support from Stewart Smith
- Make enter_rtas() private from Michael Ellerman
- PPR exception cleanups from Michael Ellerman
- Add page soft dirty tracking from Laurent Dufour
- Add support for Nvlink NPUs from Alistair Popple
- Add support for kexec on 476fpe from Alistair Popple
- Enable kernel CPU dlpar from sysfs from Nathan Fontenot
- Copy only required pieces of the mm_context_t to the paca from Michael Neuling
- Add a kmsg_dumper that flushes OPAL console output on panic from Russell Currey
- Implement save_stack_trace_regs() to enable kprobe stack tracing from Steven Rostedt
- Add HWCAP bits for Power9 from Michael Ellerman
- Fix _PAGE_PTE breaking swapoff from Aneesh Kumar K.V
- Fix _PAGE_SWP_SOFT_DIRTY breaking swapoff from Hugh Dickins
- scripts/recordmcount.pl: support data in text section on powerpc from Ulrich Weigand
- Handle R_PPC64_ENTRY relocations in modules from Ulrich Weigand
- cxl: Fix possible idr warning when contexts are released from Vaibhav Jain
- cxl: use correct operator when writing pcie config space values from Andrew Donnellan
- cxl: Fix DSI misses when the context owning task exits from Vaibhav Jain
- cxl: fix build for GCC 4.6.x from Brian Norris
- cxl: use -Werror only with CONFIG_PPC_WERROR from Brian Norris
- cxl: Enable PCI device ID for future IBM CXL adapter from Uma Krishnan
- Freescale updates from Scott: Highlights include moving QE code out of
arch/powerpc (to be shared with arm), device tree updates, and minor fixes.
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Merge tag 'powerpc-4.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Core:
- Ground work for the new Power9 MMU from Aneesh Kumar K.V
- Optimise FP/VMX/VSX context switching from Anton Blanchard
Misc:
- Various cleanups from Krzysztof Kozlowski, John Ogness, Rashmica
Gupta, Russell Currey, Gavin Shan, Daniel Axtens, Michael Neuling,
Andrew Donnellan
- Allow wrapper to work on non-english system from Laurent Vivier
- Add rN aliases to the pt_regs_offset table from Rashmica Gupta
- Fix module autoload for rackmeter & axonram drivers from Luis de
Bethencourt
- Include KVM guest test in all interrupt vectors from Paul Mackerras
- Fix DSCR inheritance over fork() from Anton Blanchard
- Make value-returning atomics & {cmp}xchg* & their atomic_ versions
fully ordered from Boqun Feng
- Print MSR TM bits in oops messages from Michael Neuling
- Add TM signal return & invalid stack selftests from Michael Neuling
- Limit EPOW reset event warnings from Vipin K Parashar
- Remove the Cell QPACE code from Rashmica Gupta
- Append linux_banner to exception information in xmon from Rashmica
Gupta
- Add selftest to check if VSRs are corrupted from Rashmica Gupta
- Remove broken GregorianDay() from Daniel Axtens
- Import Anton's context_switch2 benchmark into selftests from
Michael Ellerman
- Add selftest script to test HMI functionality from Daniel Axtens
- Remove obsolete OPAL v2 support from Stewart Smith
- Make enter_rtas() private from Michael Ellerman
- PPR exception cleanups from Michael Ellerman
- Add page soft dirty tracking from Laurent Dufour
- Add support for Nvlink NPUs from Alistair Popple
- Add support for kexec on 476fpe from Alistair Popple
- Enable kernel CPU dlpar from sysfs from Nathan Fontenot
- Copy only required pieces of the mm_context_t to the paca from
Michael Neuling
- Add a kmsg_dumper that flushes OPAL console output on panic from
Russell Currey
- Implement save_stack_trace_regs() to enable kprobe stack tracing
from Steven Rostedt
- Add HWCAP bits for Power9 from Michael Ellerman
- Fix _PAGE_PTE breaking swapoff from Aneesh Kumar K.V
- Fix _PAGE_SWP_SOFT_DIRTY breaking swapoff from Hugh Dickins
- scripts/recordmcount.pl: support data in text section on powerpc
from Ulrich Weigand
- Handle R_PPC64_ENTRY relocations in modules from Ulrich Weigand
cxl:
- cxl: Fix possible idr warning when contexts are released from
Vaibhav Jain
- cxl: use correct operator when writing pcie config space values
from Andrew Donnellan
- cxl: Fix DSI misses when the context owning task exits from Vaibhav
Jain
- cxl: fix build for GCC 4.6.x from Brian Norris
- cxl: use -Werror only with CONFIG_PPC_WERROR from Brian Norris
- cxl: Enable PCI device ID for future IBM CXL adapter from Uma
Krishnan
Freescale:
- Freescale updates from Scott: Highlights include moving QE code out
of arch/powerpc (to be shared with arm), device tree updates, and
minor fixes"
* tag 'powerpc-4.5-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (149 commits)
powerpc/module: Handle R_PPC64_ENTRY relocations
scripts/recordmcount.pl: support data in text section on powerpc
powerpc/powernv: Fix OPAL_CONSOLE_FLUSH prototype and usages
powerpc/mm: fix _PAGE_SWP_SOFT_DIRTY breaking swapoff
powerpc/mm: Fix _PAGE_PTE breaking swapoff
cxl: Enable PCI device ID for future IBM CXL adapter
cxl: use -Werror only with CONFIG_PPC_WERROR
cxl: fix build for GCC 4.6.x
powerpc: Add HWCAP bits for Power9
powerpc/powernv: Reserve PE#0 on NPU
powerpc/powernv: Change NPU PE# assignment
powerpc/powernv: Fix update of NVLink DMA mask
powerpc/powernv: Remove misleading comment in pci.c
powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing
powerpc: Fix build break due to paca mm_context_t changes
cxl: Fix DSI misses when the context owning task exits
MAINTAINERS: Update Scott Wood's e-mail address
powerpc/powernv: Fix minor off-by-one error in opal_mce_check_early_recovery()
powerpc: Fix style of self-test config prompts
powerpc/powernv: Only delay opal_rtc_read() retry when necessary
...
The get and set operations got exchanged by mistake when moving the
code from book3s.c to powerpc.c.
Fixes: 3840edc803
Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
support of 248 VCPUs.
* ARM: rewrite of the arm64 world switch in C, support for
16-bit VM identifiers. Performance counter virtualization
missed the boat.
* x86: Support for more Hyper-V features (synthetic interrupt
controller), MMU cleanups
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"PPC changes will come next week.
- s390: Support for runtime instrumentation within guests, support of
248 VCPUs.
- ARM: rewrite of the arm64 world switch in C, support for 16-bit VM
identifiers. Performance counter virtualization missed the boat.
- x86: Support for more Hyper-V features (synthetic interrupt
controller), MMU cleanups"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (115 commits)
kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL
kvm/x86: Hyper-V SynIC timers tracepoints
kvm/x86: Hyper-V SynIC tracepoints
kvm/x86: Update SynIC timers on guest entry only
kvm/x86: Skip SynIC vector check for QEMU side
kvm/x86: Hyper-V fix SynIC timer disabling condition
kvm/x86: Reorg stimer_expiration() to better control timer restart
kvm/x86: Hyper-V unify stimer_start() and stimer_restart()
kvm/x86: Drop stimer_stop() function
kvm/x86: Hyper-V timers fix incorrect logical operation
KVM: move architecture-dependent requests to arch/
KVM: renumber vcpu->request bits
KVM: document which architecture uses each request bit
KVM: Remove unused KVM_REQ_KICK to save a bit in vcpu->requests
kvm: x86: Check kvm_write_guest return value in kvm_write_wall_clock
KVM: s390: implement the RI support of guest
kvm/s390: drop unpaired smp_mb
kvm: x86: fix comment about {mmu,nested_mmu}.gva_to_gpa
KVM: x86: MMU: Use clear_page() instead of init_shadow_page_table()
arm/arm64: KVM: Detect vGIC presence at runtime
...
Currently it is possible for userspace (e.g. QEMU) to set a value
for the MSR for a guest VCPU which has both of the TS bits set,
which is an illegal combination. The result of this is that when
we execute a hrfid (hypervisor return from interrupt doubleword)
instruction to enter the guest, the CPU will take a TM Bad Thing
type of program interrupt (vector 0x700).
Now, if PR KVM is configured in the kernel along with HV KVM, we
actually handle this without crashing the host or giving hypervisor
privilege to the guest; instead what happens is that we deliver a
program interrupt to the guest, with SRR0 reflecting the address
of the hrfid instruction and SRR1 containing the MSR value at that
point. If PR KVM is not configured in the kernel, then we try to
run the host's program interrupt handler with the MMU set to the
guest context, which almost certainly causes a host crash.
This closes the hole by making kvmppc_set_msr_hv() check for the
illegal combination and force the TS field to a safe value (00,
meaning non-transactional).
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Paul Mackerras <paulus@samba.org>
The vcpu_book3s variable is assigned but never used. So remove it.
Found using cppcheck.
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
In the old DABR register, the BT (Breakpoint Translation) bit
is bit number 61. In the new DAWRX register, the WT (Watchpoint
Translation) bit is bit number 59. So to move the DABR-BT bit
into the position of the DAWRX-WT bit, it has to be shifted by
two, not only by one. This fixes hardware watchpoints in gdb of
older guests that only use the H_SET_DABR/X interface instead
of the new H_SET_MODE interface.
Cc: stable@vger.kernel.org # v3.14+
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
As we saw with the TM Bad Thing type of program interrupt occurring
on the hrfid that enters the guest, it is not completely impossible
to have a trap occurring in the guest entry/exit code, despite the
fact that the code has been written to avoid taking any traps.
This adds a check in the kvmppc_handle_exit_hv() function to detect
the case when a trap has occurred in the hypervisor-mode code, and
instead of treating it just like a trap in guest code, we now print
a message and return to userspace with a KVM_EXIT_INTERNAL_ERROR
exit reason.
Of the various interrupts that get handled in the assembly code in
the guest exit path and that can return directly to the guest, the
only one that can occur when MSR.HV=1 and MSR.EE=0 is machine check
(other than system call, which we can avoid just by not doing a sc
instruction). Therefore this adds code to the machine check path to
ensure that if the MCE occurred in hypervisor mode, we exit to the
host rather than trying to continue the guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Create a single function that flushes everything (FP, VMX, VSX, SPE).
Doing this all at once means we only do one MSR write.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Create a single function that gives everything up (FP, VMX, VSX, SPE).
Doing this all at once means we only do one MSR write.
A context switch microbenchmark using yield():
http://ozlabs.org/~anton/junkcode/context_switch2.c
./context_switch2 --test=yield --fp --altivec --vector 0 0
shows an improvement of 3% on POWER8.
Signed-off-by: Anton Blanchard <anton@samba.org>
[mpe: giveup_all() needs to be EXPORT_SYMBOL'ed]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The enable_kernel_*() functions leave the relevant MSR bits enabled
until we exit the kernel sometime later. Create disable versions
that wrap the kernel use of FP, Altivec VSX or SPE.
While we don't want to disable it normally for performance reasons
(MSR writes are slow), it will be used for a debug boot option that
does this and catches bad uses in other areas of the kernel.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Let's reuse the new common function for VPCU lookup by id.
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[split out the new function into a separate patch]
In another patch kvm_is_visible_gfn is maken return bool due to this
function only returns zero or one as its return value, let's also make
kvmppc_visible_gpa return bool to keep consistent.
No functional change.
Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- x86: work around two nasty cases where a benign exception occurs while
another is being delivered. The endless stream of exceptions causes an
infinite loop in the processor, which not even NMIs or SMIs can interrupt;
in the virt case, there is no possibility to exit to the host either.
- x86: support for Skylake per-guest TSC rate. Long supported by AMD,
the patches mostly move things from there to common arch/x86/kvm/ code.
- generic: remove local_irq_save/restore from the guest entry and exit
paths when context tracking is enabled. The patches are a few months
old, but we discussed them again at kernel summit. Andy will pick up
from here and, in 4.5, try to remove it from the user entry/exit paths.
- PPC: Two bug fixes, see merge commit 370289756b for details.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull second batch of kvm updates from Paolo Bonzini:
"Four changes:
- x86: work around two nasty cases where a benign exception occurs
while another is being delivered. The endless stream of exceptions
causes an infinite loop in the processor, which not even NMIs or
SMIs can interrupt; in the virt case, there is no possibility to
exit to the host either.
- x86: support for Skylake per-guest TSC rate. Long supported by
AMD, the patches mostly move things from there to common
arch/x86/kvm/ code.
- generic: remove local_irq_save/restore from the guest entry and
exit paths when context tracking is enabled. The patches are a few
months old, but we discussed them again at kernel summit. Andy
will pick up from here and, in 4.5, try to remove it from the user
entry/exit paths.
- PPC: Two bug fixes, see merge commit 370289756b for details"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (21 commits)
KVM: x86: rename update_db_bp_intercept to update_bp_intercept
KVM: svm: unconditionally intercept #DB
KVM: x86: work around infinite loop in microcode when #AC is delivered
context_tracking: avoid irq_save/irq_restore on guest entry and exit
context_tracking: remove duplicate enabled check
KVM: VMX: Dump TSC multiplier in dump_vmcs()
KVM: VMX: Use a scaled host TSC for guest readings of MSR_IA32_TSC
KVM: VMX: Setup TSC scaling ratio when a vcpu is loaded
KVM: VMX: Enable and initialize VMX TSC scaling
KVM: x86: Use the correct vcpu's TSC rate to compute time scale
KVM: x86: Move TSC scaling logic out of call-back read_l1_tsc()
KVM: x86: Move TSC scaling logic out of call-back adjust_tsc_offset()
KVM: x86: Replace call-back compute_tsc_offset() with a common function
KVM: x86: Replace call-back set_tsc_khz() with a common function
KVM: x86: Add a common TSC scaling function
KVM: x86: Add a common TSC scaling ratio field in kvm_vcpu_arch
KVM: x86: Collect information for setting TSC scaling ratio
KVM: x86: declare a few variables as __read_mostly
KVM: x86: merge handle_mmio_page_fault and handle_mmio_page_fault_common
KVM: PPC: Book3S HV: Don't dynamically split core when already split
...
- Kconfig: remove BE-only platforms from LE kernel build from Boqun Feng
- Refresh ps3_defconfig from Geoff Levand
- Emit GNU & SysV hashes for the vdso from Michael Ellerman
- Define an enum for the bolted SLB indexes from Anshuman Khandual
- Use a local to avoid multiple calls to get_slb_shadow() from Michael Ellerman
- Add gettimeofday() benchmark from Michael Neuling
- Avoid link stack corruption in __get_datapage() from Michael Neuling
- Add virt_to_pfn and use this instead of opencoding from Aneesh Kumar K.V
- Add ppc64le_defconfig from Michael Ellerman
- pseries: extract of_helpers module from Andy Shevchenko
- Correct string length in pseries_of_derive_parent() from Nathan Fontenot
- Free the MSI bitmap if it was slab allocated from Denis Kirjanov
- Shorten irq_chip name for the SIU from Christophe Leroy
- Wait 1s for secondaries to enter OPAL during kexec from Samuel Mendoza-Jonas
- Fix _ALIGN_* errors due to type difference. from Aneesh Kumar K.V
- powerpc/pseries/hvcserver: don't memset pi_buff if it is null from Colin Ian King
- Disable hugepd for 64K page size. from Aneesh Kumar K.V
- Differentiate between hugetlb and THP during page walk from Aneesh Kumar K.V
- Make PCI non-optional for pseries from Michael Ellerman
- Individual System V IPC system calls from Sam bobroff
- Add selftest of unmuxed IPC calls from Michael Ellerman
- discard .exit.data at runtime from Stephen Rothwell
- Delete old orphaned PrPMC 280/2800 DTS and boot file. from Paul Gortmaker
- Use of_get_next_parent to simplify code from Christophe Jaillet
- Paginate some xmon output from Sam bobroff
- Add some more elements to the xmon PACA dump from Michael Ellerman
- Allow the tm-syscall selftest to build with old headers from Michael Ellerman
- Run EBB selftests only on POWER8 from Denis Kirjanov
- Drop CONFIG_TUNE_CELL in favour of CONFIG_CELL_CPU from Michael Ellerman
- Avoid reference to potentially freed memory in prom.c from Christophe Jaillet
- Quieten boot wrapper output with run_cmd from Geoff Levand
- EEH fixes and cleanups from Gavin Shan
- Fix recursive fenced PHB on Broadcom shiner adapter from Gavin Shan
- Use of_get_next_parent() in of_get_ibm_chip_id() from Michael Ellerman
- Fix section mismatch warning in msi_bitmap_alloc() from Denis Kirjanov
- Fix ps3-lpm white space from Rudhresh Kumar J
- Fix ps3-vuart null dereference from Colin King
- nvram: Add missing kfree in error path from Christophe Jaillet
- nvram: Fix function name in some errors messages. from Christophe Jaillet
- drivers/macintosh: adb: fix misleading Kconfig help text from Aaro Koskinen
- agp/uninorth: fix a memleak in create_gatt_table from Denis Kirjanov
- cxl: Free virtual PHB when removing from Andrew Donnellan
- scripts/kconfig/Makefile: Allow KBUILD_DEFCONFIG to be a target from Michael Ellerman
- scripts/kconfig/Makefile: Fix KBUILD_DEFCONFIG check when building with O= from Michael Ellerman
- Freescale updates from Scott: Highlights include 64-bit book3e kexec/kdump
support, a rework of the qoriq clock driver, device tree changes including
qoriq fman nodes, support for a new 85xx board, and some fixes.
- MPC5xxx updates from Anatolij: Highlights include a driver for MPC512x
LocalPlus Bus FIFO with its device tree binding documentation, mpc512x
device tree updates and some minor fixes.
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Merge tag 'powerpc-4.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Kconfig: remove BE-only platforms from LE kernel build from Boqun
Feng
- Refresh ps3_defconfig from Geoff Levand
- Emit GNU & SysV hashes for the vdso from Michael Ellerman
- Define an enum for the bolted SLB indexes from Anshuman Khandual
- Use a local to avoid multiple calls to get_slb_shadow() from Michael
Ellerman
- Add gettimeofday() benchmark from Michael Neuling
- Avoid link stack corruption in __get_datapage() from Michael Neuling
- Add virt_to_pfn and use this instead of opencoding from Aneesh Kumar
K.V
- Add ppc64le_defconfig from Michael Ellerman
- pseries: extract of_helpers module from Andy Shevchenko
- Correct string length in pseries_of_derive_parent() from Nathan
Fontenot
- Free the MSI bitmap if it was slab allocated from Denis Kirjanov
- Shorten irq_chip name for the SIU from Christophe Leroy
- Wait 1s for secondaries to enter OPAL during kexec from Samuel
Mendoza-Jonas
- Fix _ALIGN_* errors due to type difference, from Aneesh Kumar K.V
- powerpc/pseries/hvcserver: don't memset pi_buff if it is null from
Colin Ian King
- Disable hugepd for 64K page size, from Aneesh Kumar K.V
- Differentiate between hugetlb and THP during page walk from Aneesh
Kumar K.V
- Make PCI non-optional for pseries from Michael Ellerman
- Individual System V IPC system calls from Sam bobroff
- Add selftest of unmuxed IPC calls from Michael Ellerman
- discard .exit.data at runtime from Stephen Rothwell
- Delete old orphaned PrPMC 280/2800 DTS and boot file, from Paul
Gortmaker
- Use of_get_next_parent to simplify code from Christophe Jaillet
- Paginate some xmon output from Sam bobroff
- Add some more elements to the xmon PACA dump from Michael Ellerman
- Allow the tm-syscall selftest to build with old headers from Michael
Ellerman
- Run EBB selftests only on POWER8 from Denis Kirjanov
- Drop CONFIG_TUNE_CELL in favour of CONFIG_CELL_CPU from Michael
Ellerman
- Avoid reference to potentially freed memory in prom.c from Christophe
Jaillet
- Quieten boot wrapper output with run_cmd from Geoff Levand
- EEH fixes and cleanups from Gavin Shan
- Fix recursive fenced PHB on Broadcom shiner adapter from Gavin Shan
- Use of_get_next_parent() in of_get_ibm_chip_id() from Michael
Ellerman
- Fix section mismatch warning in msi_bitmap_alloc() from Denis
Kirjanov
- Fix ps3-lpm white space from Rudhresh Kumar J
- Fix ps3-vuart null dereference from Colin King
- nvram: Add missing kfree in error path from Christophe Jaillet
- nvram: Fix function name in some errors messages, from Christophe
Jaillet
- drivers/macintosh: adb: fix misleading Kconfig help text from Aaro
Koskinen
- agp/uninorth: fix a memleak in create_gatt_table from Denis Kirjanov
- cxl: Free virtual PHB when removing from Andrew Donnellan
- scripts/kconfig/Makefile: Allow KBUILD_DEFCONFIG to be a target from
Michael Ellerman
- scripts/kconfig/Makefile: Fix KBUILD_DEFCONFIG check when building
with O= from Michael Ellerman
- Freescale updates from Scott: Highlights include 64-bit book3e
kexec/kdump support, a rework of the qoriq clock driver, device tree
changes including qoriq fman nodes, support for a new 85xx board, and
some fixes.
- MPC5xxx updates from Anatolij: Highlights include a driver for
MPC512x LocalPlus Bus FIFO with its device tree binding
documentation, mpc512x device tree updates and some minor fixes.
* tag 'powerpc-4.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (106 commits)
powerpc/msi: Fix section mismatch warning in msi_bitmap_alloc()
powerpc/prom: Use of_get_next_parent() in of_get_ibm_chip_id()
powerpc/pseries: Correct string length in pseries_of_derive_parent()
powerpc/e6500: hw tablewalk: make sure we invalidate and write to the same tlb entry
powerpc/mpc85xx: Add FSL QorIQ DPAA FMan support to the SoC device tree(s)
powerpc/mpc85xx: Create dts components for the FSL QorIQ DPAA FMan
powerpc/fsl: Add #clock-cells and clockgen label to clockgen nodes
powerpc: handle error case in cpm_muram_alloc()
powerpc: mpic: use IRQCHIP_SKIP_SET_WAKE instead of redundant mpic_irq_set_wake
powerpc/book3e-64: Enable kexec
powerpc/book3e-64/kexec: Set "r4 = 0" when entering spinloop
powerpc/booke: Only use VIRT_PHYS_OFFSET on booke32
powerpc/book3e-64/kexec: Enable SMP release
powerpc/book3e-64/kexec: create an identity TLB mapping
powerpc/book3e-64: Don't limit paca to 256 MiB
powerpc/book3e/kdump: Enable crash_kexec_wait_realmode
powerpc/book3e: support CONFIG_RELOCATABLE
powerpc/booke64: Fix args to copy_and_flush
powerpc/book3e-64: rename interrupt_end_book3e with __end_interrupts
powerpc/e6500: kexec: Handle hardware threads
...
In static micro-threading modes, the dynamic micro-threading code
is supposed to be disabled, because subcores can't make independent
decisions about what micro-threading mode to put the core in - there is
only one micro-threading mode for the whole core. The code that
implements dynamic micro-threading checks for this, except that the
check was missed in one case. This means that it is possible for a
subcore in static 2-way micro-threading mode to try to put the core
into 4-way micro-threading mode, which usually leads to stuck CPUs,
spinlock lockups, and other stalls in the host.
The problem was in the can_split_piggybacked_subcores() function, which
should always return false if the system is in a static micro-threading
mode. This fixes the problem by making can_split_piggybacked_subcores()
use subcore_config_ok() for its checks, as subcore_config_ok() includes
the necessary check for the static micro-threading modes.
Credit to Gautham Shenoy for working out that the reason for the hangs
and stalls we were seeing was that we were trying to do dynamic 4-way
micro-threading while we were in static 2-way mode.
Fixes: b4deba5c41
Cc: vger@stable.kernel.org # v4.3
Signed-off-by: Paul Mackerras <paulus@samba.org>
When handling a hypervisor data or instruction storage interrupt (HDSI
or HISI), we look up the SLB entry for the address being accessed in
order to translate the effective address to a virtual address which can
be looked up in the guest HPT. This lookup can occasionally fail due
to the guest replacing an SLB entry without invalidating the evicted
SLB entry. In this situation an ERAT (effective to real address
translation cache) entry can persist and be used by the hardware even
though there is no longer a corresponding SLB entry.
Previously we would just deliver a data or instruction storage interrupt
(DSI or ISI) to the guest in this case. However, this is not correct
and has been observed to cause guests to crash, typically with a
data storage protection interrupt on a store to the vmemmap area.
Instead, what we do now is to synthesize a data or instruction segment
interrupt. That should cause the guest to reload an appropriate entry
into the SLB and retry the faulting instruction. If it still faults,
we should find an appropriate SLB entry next time and be able to handle
the fault.
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
handling.
PPC: Mostly bug fixes.
ARM: No big features, but many small fixes and prerequisites including:
- a number of fixes for the arch-timer
- introducing proper level-triggered semantics for the arch-timers
- a series of patches to synchronously halt a guest (prerequisite for
IRQ forwarding)
- some tracepoint improvements
- a tweak for the EL2 panic handlers
- some more VGIC cleanups getting rid of redundant state
x86: quite a few changes:
- support for VT-d posted interrupts (i.e. PCI devices can inject
interrupts directly into vCPUs). This introduces a new component (in
virt/lib/) that connects VFIO and KVM together. The same infrastructure
will be used for ARM interrupt forwarding as well.
- more Hyper-V features, though the main one Hyper-V synthetic interrupt
controller will have to wait for 4.5. These will let KVM expose Hyper-V
devices.
- nested virtualization now supports VPID (same as PCID but for vCPUs)
which makes it quite a bit faster
- for future hardware that supports NVDIMM, there is support for clflushopt,
clwb, pcommit
- support for "split irqchip", i.e. LAPIC in kernel + IOAPIC/PIC/PIT in
userspace, which reduces the attack surface of the hypervisor
- obligatory smattering of SMM fixes
- on the guest side, stable scheduler clock support was rewritten to not
require help from the hypervisor.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"First batch of KVM changes for 4.4.
s390:
A bunch of fixes and optimizations for interrupt and time handling.
PPC:
Mostly bug fixes.
ARM:
No big features, but many small fixes and prerequisites including:
- a number of fixes for the arch-timer
- introducing proper level-triggered semantics for the arch-timers
- a series of patches to synchronously halt a guest (prerequisite
for IRQ forwarding)
- some tracepoint improvements
- a tweak for the EL2 panic handlers
- some more VGIC cleanups getting rid of redundant state
x86:
Quite a few changes:
- support for VT-d posted interrupts (i.e. PCI devices can inject
interrupts directly into vCPUs). This introduces a new
component (in virt/lib/) that connects VFIO and KVM together.
The same infrastructure will be used for ARM interrupt
forwarding as well.
- more Hyper-V features, though the main one Hyper-V synthetic
interrupt controller will have to wait for 4.5. These will let
KVM expose Hyper-V devices.
- nested virtualization now supports VPID (same as PCID but for
vCPUs) which makes it quite a bit faster
- for future hardware that supports NVDIMM, there is support for
clflushopt, clwb, pcommit
- support for "split irqchip", i.e. LAPIC in kernel +
IOAPIC/PIC/PIT in userspace, which reduces the attack surface of
the hypervisor
- obligatory smattering of SMM fixes
- on the guest side, stable scheduler clock support was rewritten
to not require help from the hypervisor"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (123 commits)
KVM: VMX: Fix commit which broke PML
KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0()
KVM: x86: allow RSM from 64-bit mode
KVM: VMX: fix SMEP and SMAP without EPT
KVM: x86: move kvm_set_irq_inatomic to legacy device assignment
KVM: device assignment: remove pointless #ifdefs
KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomic
KVM: x86: zero apic_arb_prio on reset
drivers/hv: share Hyper-V SynIC constants with userspace
KVM: x86: handle SMBASE as physical address in RSM
KVM: x86: add read_phys to x86_emulate_ops
KVM: x86: removing unused variable
KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configs
KVM: arm/arm64: Merge vgic_set_lr() and vgic_sync_lr_elrsr()
KVM: arm/arm64: Clean up vgic_retire_lr() and surroundings
KVM: arm/arm64: Optimize away redundant LR tracking
KVM: s390: use simple switch statement as multiplexer
KVM: s390: drop useless newline in debugging data
KVM: s390: SCA must not cross page boundaries
KVM: arm: Do not indent the arguments of DECLARE_BITMAP
...
This reverts commit 9678cdaae9 ("Use the POWER8 Micro Partition
Prefetch Engine in KVM HV on POWER8") because the original commit had
multiple, partly self-cancelling bugs, that could cause occasional
memory corruption.
In fact the logmpp instruction was incorrectly using register r0 as the
source of the buffer address and operation code, and depending on what
was in r0, it would either do nothing or corrupt the 64k page pointed to
by r0.
The logmpp instruction encoding and the operation code definitions could
be corrected, but then there is the problem that there is no clearly
defined way to know when the hardware has finished writing to the
buffer.
The original commit attempted to work around this by aborting the
write-out before starting the prefetch, but this is ineffective in the
case where the virtual core is now executing on a different physical
core from the one where the write-out was initiated.
These problems plus advice from the hardware designers not to use the
function (since the measured performance improvement from using the
feature was actually mostly negative), mean that reverting the code is
the best option.
Fixes: 9678cdaae9 ("Use the POWER8 Micro Partition Prefetch Engine in KVM HV on POWER8")
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently a CPU running a guest can receive a H_DOORBELL in the
following two cases:
1) When the CPU is napping due to CEDE or there not being a guest
vcpu.
2) The CPU is running the guest vcpu.
Case 1), the doorbell message is not cleared since we were waking up
from nap. Hence when the EE bit gets set on transition from guest to
host, the H_DOORBELL interrupt is delivered to the host and the
corresponding handler is invoked.
However in Case 2), the message gets cleared by the action of taking
the H_DOORBELL interrupt. Since the CPU was running a guest, instead
of invoking the doorbell handler, the code invokes the second-level
interrupt handler to switch the context from the guest to the host. At
this point the setting of the EE bit doesn't result in the CPU getting
the doorbell interrupt since it has already been delivered once. So,
the handler for this doorbell is never invoked!
This causes softlockups if the missed DOORBELL was an IPI sent from a
sibling subcore on the same CPU.
This patch fixes it by explitly invoking the doorbell handler on the
exit path if the exit reason is H_DOORBELL similar to the way an
EXTERNAL interrupt is handled. Since this will also handle Case 1), we
can unconditionally clear the doorbell message in
kvmppc_check_wake_reason.
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
QEMU assumes 32 memslots if this extension is not implemented. Although,
current value of KVM_USER_MEM_SLOTS is 32, once KVM_USER_MEM_SLOTS
changes QEMU would take a wrong value.
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This fixes a bug where the old HPTE value returned by H_REMOVE has
the valid bit clear if the HPTE was an absent HPTE, as happens for
HPTEs for emulated MMIO pages and for RAM pages that have been paged
out by the host. If the absent bit is set, we clear it and set the
valid bit, because from the guest's point of view, the HPTE is valid.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Currently the KVM_PPC_ALLOCATE_HTAB will try to allocate the requested
size of HPT, and if that is not possible, then try to allocate smaller
sizes (by factors of 2) until either a minimum is reached or the
allocation succeeds. This is not ideal for userspace, particularly in
migration scenarios, where the destination VM really does require the
size requested. Also, the minimum HPT size of 256kB may be
insufficient for the guest to run successfully.
This removes the fallback to smaller sizes on allocation failure for
the KVM_PPC_ALLOCATE_HTAB ioctl. The fallback still exists for the
case where the HPT is allocated at the time the first VCPU is run, if
no HPT has been allocated by ioctl by that time.
Signed-off-by: Paul Mackerras <paulus@samba.org>
For the machine check interrupt that happens while we are in the guest,
kvm layer attempts the recovery, and then delivers the machine check interrupt
directly to the guest if recovery fails. On successful recovery we go back to
normal functioning of the guest. But there can be cases where a machine check
interrupt can happen with MSR(RI=0) while we are in the guest. This means
MC interrupt is unrecoverable and we have to deliver a machine check to the
guest since the machine check interrupt might have trashed valid values in
SRR0/1. The current implementation do not handle this case, causing guest
to crash with Bad kernel stack pointer instead of machine check oops message.
[26281.490060] Bad kernel stack pointer 3fff9ccce5b0 at c00000000000490c
[26281.490434] Oops: Bad kernel stack pointer, sig: 6 [#1]
[26281.490472] SMP NR_CPUS=2048 NUMA pSeries
This patch fixes this issue by checking MSR(RI=0) in KVM layer and forwarding
unrecoverable interrupt to guest which then panics with proper machine check
Oops message.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Fix couple of cases where we shift left a 32-bit
value thus might get truncated results on 64-bit
targets.
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Suggested-by: Scott Wood <scotttwood@freescale.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Emulate TMCFG0 TMRN register exposing one HW thread per vcpu.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
[Laurentiu.Tudor@freescale.com: rebased on latest kernel, use
define instead of hardcoded value, moved code in own function]
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Acked-by: Scott Wood <scotttwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The function can return negative value.
The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/assign_signed_to_unsigned.cocci [1].
[1]: http://permalink.gmane.org/gmane.linux.kernel/2046107
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
We need to properly identify whether a hugepage is an explicit or
a transparent hugepage in follow_huge_addr(). We used to depend
on hugepage shift argument to do that. But in some case that can
result in wrong results. For ex:
On finding a transparent hugepage we set hugepage shift to PMD_SHIFT.
But we can end up clearing the thp pte, via pmdp_huge_get_and_clear.
We do prevent reusing the pfn page via the usage of
kick_all_cpus_sync(). But that happens after we updated the pte to 0.
Hence in follow_huge_addr() we can find hugepage shift set, but transparent
huge page check fail for a thp pte.
NOTE: We fixed a variant of this race against thp split in commit
691e95fd73
("powerpc/mm/thp: Make page table walk safe against thp split/collapse")
Without this patch, we may hit the BUG_ON(flags & FOLL_GET) in
follow_page_mask occasionally.
In the long term, we may want to switch ppc64 64k page size config to
enable CONFIG_ARCH_WANT_GENERAL_HUGETLB
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Access to the kvm->buses (like with the kvm_io_bus_read() and -write()
functions) has to be protected via the kvm->srcu lock.
The kvmppc_h_logical_ci_load() and -store() functions are missing
this lock so far, so let's add it there, too.
This fixes the problem that the kernel reports "suspicious RCU usage"
when lock debugging is enabled.
Cc: stable@vger.kernel.org # v4.1+
Fixes: 99342cf804
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
In guest_exit_cont we call kvmhv_commence_exit which expects the trap
number as the argument. However r3 doesn't contain the trap number at
this point and as a result we would be calling the function with a
spurious trap number.
Fix this by copying r12 into r3 before calling kvmhv_commence_exit as
r12 contains the trap number.
Cc: stable@vger.kernel.org # v4.1+
Fixes: eddb60fb14
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This fixes a bug which results in stale vcore pointers being left in
the per-cpu preempted vcore lists when a VM is destroyed. The result
of the stale vcore pointers is usually either a crash or a lockup
inside collect_piggybacks() when another VM is run. A typical
lockup message looks like:
[ 472.161074] NMI watchdog: BUG: soft lockup - CPU#24 stuck for 22s! [qemu-system-ppc:7039]
[ 472.161204] Modules linked in: kvm_hv kvm_pr kvm xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw ses enclosure shpchp rtc_opal i2c_opal powernv_rng binfmt_misc dm_service_time scsi_dh_alua radeon i2c_algo_bit drm_kms_helper ttm drm tg3 ptp pps_core cxgb3 ipr i2c_core mdio dm_multipath [last unloaded: kvm_hv]
[ 472.162111] CPU: 24 PID: 7039 Comm: qemu-system-ppc Not tainted 4.2.0-kvm+ #49
[ 472.162187] task: c000001e38512750 ti: c000001e41bfc000 task.ti: c000001e41bfc000
[ 472.162262] NIP: c00000000096b094 LR: c00000000096b08c CTR: c000000000111130
[ 472.162337] REGS: c000001e41bff520 TRAP: 0901 Not tainted (4.2.0-kvm+)
[ 472.162399] MSR: 9000000100009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 24848844 XER: 00000000
[ 472.162588] CFAR: c00000000096b0ac SOFTE: 1
GPR00: c000000000111170 c000001e41bff7a0 c00000000127df00 0000000000000001
GPR04: 0000000000000003 0000000000000001 0000000000000000 0000000000874821
GPR08: c000001e41bff8e0 0000000000000001 0000000000000000 d00000000efde740
GPR12: c000000000111130 c00000000fdae400
[ 472.163053] NIP [c00000000096b094] _raw_spin_lock_irqsave+0xa4/0x130
[ 472.163117] LR [c00000000096b08c] _raw_spin_lock_irqsave+0x9c/0x130
[ 472.163179] Call Trace:
[ 472.163206] [c000001e41bff7a0] [c000001e41bff7f0] 0xc000001e41bff7f0 (unreliable)
[ 472.163295] [c000001e41bff7e0] [c000000000111170] __wake_up+0x40/0x90
[ 472.163375] [c000001e41bff830] [d00000000efd6fc0] kvmppc_run_core+0x1240/0x1950 [kvm_hv]
[ 472.163465] [c000001e41bffa30] [d00000000efd8510] kvmppc_vcpu_run_hv+0x5a0/0xd90 [kvm_hv]
[ 472.163559] [c000001e41bffb70] [d00000000e9318a4] kvmppc_vcpu_run+0x44/0x60 [kvm]
[ 472.163653] [c000001e41bffba0] [d00000000e92e674] kvm_arch_vcpu_ioctl_run+0x64/0x170 [kvm]
[ 472.163745] [c000001e41bffbe0] [d00000000e9263a8] kvm_vcpu_ioctl+0x538/0x7b0 [kvm]
[ 472.163834] [c000001e41bffd40] [c0000000002d0f50] do_vfs_ioctl+0x480/0x7c0
[ 472.163910] [c000001e41bffde0] [c0000000002d1364] SyS_ioctl+0xd4/0xf0
[ 472.163986] [c000001e41bffe30] [c000000000009260] system_call+0x38/0xd0
[ 472.164060] Instruction dump:
[ 472.164098] ebc1fff0 ebe1fff8 7c0803a6 4e800020 60000000 60000000 60420000 8bad02e2
[ 472.164224] 7fc3f378 4b6a57c1 60000000 7c210b78 <e92d0000> 89290009 792affe3 40820070
The bug is that kvmppc_run_vcpu does not correctly handle the case
where a vcpu task receives a signal while its guest vcpu is executing
in the guest as a result of being piggy-backed onto the execution of
another vcore. In that case we need to wait for the vcpu to finish
executing inside the guest, and then remove this vcore from the
preempted vcores list. That way, we avoid leaving this vcpu's vcore
on the preempted vcores list when the vcpu gets interrupted.
Fixes: ec25716508
Reported-by: Thomas Huth <thuth@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This new statistic can help diagnosing VCPUs that, for any reason,
trigger bad behavior of halt_poll_ns autotuning.
For example, say halt_poll_ns = 480000, and wakeups are spaced exactly
like 479us, 481us, 479us, 481us. Then KVM always fails polling and wastes
10+20+40+80+160+320+480 = 1110 microseconds out of every
479+481+479+481+479+481+479 = 3359 microseconds. The VCPU then
is consuming about 30% more CPU than it would use without
polling. This would show as an abnormally high number of
attempted polling compared to the successful polls.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com<
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The code that handles the case when we receive a H_DOORBELL interrupt
has a comment which says "Hypervisor doorbell - exit only if host IPI
flag set". However, the current code does not actually check if the
host IPI flag is set. This is due to a comparison instruction that
got missed.
As a result, the current code performs the exit to host only
if some sibling thread or a sibling sub-core is exiting to the
host. This implies that, an IPI sent to a sibling core in
(subcores-per-core != 1) mode will be missed by the host unless the
sibling core is on the exit path to the host.
This patch adds the missing comparison operation which will ensure
that when HOST_IPI flag is set, we unconditionally exit to the host.
Fixes: 66feed61cd
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The current dynamic micro-threading code has a race due to which a
secondary thread naps when it is supposed to be running a vcpu. As a
side effect of this, on a guest exit, the primary thread in
kvmppc_wait_for_nap() finds that this secondary thread hasn't cleared
its vcore pointer. This results in "CPU X seems to be stuck!"
warnings.
The race is possible since the primary thread on exiting the guests
only waits for all the secondaries to clear its vcore pointer. It
subsequently expects the secondary threads to enter nap while it
unsplits the core. A secondary thread which hasn't yet entered the nap
will loop in kvm_no_guest until its vcore pointer and the do_nap flag
are unset. Once the core has been unsplit, a new vcpu thread can grab
the core and set the do_nap flag *before* setting the vcore pointers
of the secondary. As a result, the secondary thread will now enter nap
via kvm_unsplit_nap instead of running the guest vcpu.
Fix this by setting the do_nap flag after setting the vcore pointer in
the PACA of the secondary in kvmppc_run_core. Also, ensure that a
secondary thread doesn't nap in kvm_unsplit_nap when the vcore pointer
in its PACA struct is set.
Fixes: b4deba5c41
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
In 64 bit kernels, the Fixed Point Exception Register (XER) is a 64
bit field (e.g. in kvm_regs and kvm_vcpu_arch) and in most places it is
accessed as such.
This patch corrects places where it is accessed as a 32 bit field by a
64 bit kernel. In some cases this is via a 32 bit load or store
instruction which, depending on endianness, will cause either the
lower or upper 32 bits to be missed. In another case it is cast as a
u32, causing the upper 32 bits to be cleared.
This patch corrects those places by extending the access methods to
64 bits.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Whenever a vcore state is VCORE_PREEMPT we need to be counting stolen
time for it. This currently isn't the case when we have a vcore that
no longer has any runnable threads in it but still has a runner task,
so we do an explicit call to kvmppc_core_start_stolen() in that case.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
When a vcore gets preempted, we put it on the preempted vcore list for
the current CPU. The runner task then calls schedule() and comes back
some time later and takes itself off the list. We need to be careful
to lock the list that it was put onto, which may not be the list for the
current CPU since the runner task may have moved to another CPU.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds implementations for the H_CLEAR_REF (test and clear reference
bit) and H_CLEAR_MOD (test and clear changed bit) hypercalls.
When clearing the reference or change bit in the guest view of the HPTE,
we also have to clear it in the real HPTE so that we can detect future
references or changes. When we do so, we transfer the R or C bit value
to the rmap entry for the underlying host page so that kvm_age_hva_hv(),
kvm_test_age_hva_hv() and kvmppc_hv_get_dirty_log() know that the page
has been referenced and/or changed.
These hypercalls are not used by Linux guests. These implementations
have been tested using a FreeBSD guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This fixes a bug in the tracking of pages that get modified by the
guest. If the guest creates a large-page HPTE, writes to memory
somewhere within the large page, and then removes the HPTE, we only
record the modified state for the first normal page within the large
page, when in fact the guest might have modified some other normal
page within the large page.
To fix this we use some unused bits in the rmap entry to record the
order (log base 2) of the size of the page that was modified, when
removing an HPTE. Then in kvm_test_clear_dirty_npages() we use that
order to return the correct number of modified pages.
The same thing could in principle happen when removing a HPTE at the
host's request, i.e. when paging out a page, except that we never
page out large pages, and the guest can only create large-page HPTEs
if the guest RAM is backed by large pages. However, we also fix
this case for the sake of future-proofing.
The reference bit is also subject to the same loss of information. We
don't make the same fix here for the reference bit because there isn't
an interface for userspace to find out which pages the guest has
referenced, whereas there is one for userspace to find out which pages
the guest has modified. Because of this loss of information, the
kvm_age_hva_hv() and kvm_test_age_hva_hv() functions might incorrectly
say that a page has not been referenced when it has, but that doesn't
matter greatly because we never page or swap out large pages.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The reference (R) and change (C) bits in a HPT entry can be set by
hardware at any time up until the HPTE is invalidated and the TLB
invalidation sequence has completed. This means that when removing
a HPTE, we need to read the HPTE after the invalidation sequence has
completed in order to obtain reliable values of R and C. The code
in kvmppc_do_h_remove() used to do this. However, commit 6f22bd3265
("KVM: PPC: Book3S HV: Make HTAB code LE host aware") removed the
read after invalidation as a side effect of other changes. This
restores the read of the HPTE after invalidation.
The user-visible effect of this bug would be that when migrating a
guest, there is a small probability that a page modified by the guest
and then unmapped by the guest might not get re-transmitted and thus
the destination might end up with a stale copy of the page.
Fixes: 6f22bd3265
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This builds on the ability to run more than one vcore on a physical
core by using the micro-threading (split-core) modes of the POWER8
chip. Previously, only vcores from the same VM could be run together,
and (on POWER8) only if they had just one thread per core. With the
ability to split the core on guest entry and unsplit it on guest exit,
we can run up to 8 vcpu threads from up to 4 different VMs, and we can
run multiple vcores with 2 or 4 vcpus per vcore.
Dynamic micro-threading is only available if the static configuration
of the cores is whole-core mode (unsplit), and only on POWER8.
To manage this, we introduce a new kvm_split_mode struct which is
shared across all of the subcores in the core, with a pointer in the
paca on each thread. In addition we extend the core_info struct to
have information on each subcore. When deciding whether to add a
vcore to the set already on the core, we now have two possibilities:
(a) piggyback the vcore onto an existing subcore, or (b) start a new
subcore.
Currently, when any vcpu needs to exit the guest and switch to host
virtual mode, we interrupt all the threads in all subcores and switch
the core back to whole-core mode. It may be possible in future to
allow some of the subcores to keep executing in the guest while
subcore 0 switches to the host, but that is not implemented in this
patch.
This adds a module parameter called dynamic_mt_modes which controls
which micro-threading (split-core) modes the code will consider, as a
bitmap. In other words, if it is 0, no micro-threading mode is
considered; if it is 2, only 2-way micro-threading is considered; if
it is 4, only 4-way, and if it is 6, both 2-way and 4-way
micro-threading mode will be considered. The default is 6.
With this, we now have secondary threads which are the primary thread
for their subcore and therefore need to do the MMU switch. These
threads will need to be started even if they have no vcpu to run, so
we use the vcore pointer in the PACA rather than the vcpu pointer to
trigger them.
It is now possible for thread 0 to find that an exit has been
requested before it gets to switch the subcore state to the guest. In
that case we haven't added the guest's timebase offset to the
timebase, so we need to be careful not to subtract the offset in the
guest exit path. In fact we just skip the whole path that switches
back to host context, since we haven't switched to the guest context.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
When running a virtual core of a guest that is configured with fewer
threads per core than the physical cores have, the extra physical
threads are currently unused. This makes it possible to use them to
run one or more other virtual cores from the same guest when certain
conditions are met. This applies on POWER7, and on POWER8 to guests
with one thread per virtual core. (It doesn't apply to POWER8 guests
with multiple threads per vcore because they require a 1-1 virtual to
physical thread mapping in order to be able to use msgsndp and the
TIR.)
The idea is that we maintain a list of preempted vcores for each
physical cpu (i.e. each core, since the host runs single-threaded).
Then, when a vcore is about to run, it checks to see if there are
any vcores on the list for its physical cpu that could be
piggybacked onto this vcore's execution. If so, those additional
vcores are put into state VCORE_PIGGYBACK and their runnable VCPU
threads are started as well as the original vcore, which is called
the master vcore.
After the vcores have exited the guest, the extra ones are put back
onto the preempted list if any of their VCPUs are still runnable and
not idle.
This means that vcpu->arch.ptid is no longer necessarily the same as
the physical thread that the vcpu runs on. In order to make it easier
for code that wants to send an IPI to know which CPU to target, we
now store that in a new field in struct vcpu_arch, called thread_cpu.
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
On this switch branch the regs initialization
doesn't happen so add it.
This was found with the help of a static
code analysis tool.
Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
