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vmm: permit some IPIs to be handled by userspace

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Add VM_EXITCODE_IPI to permit returning unhandled IPIs to userland.
INIT and STARTUP IPIs are now returned to userland. Due to backward
compatibility reasons, a new capability is added for enabling
VM_EXITCODE_IPI.

Reviewed by:		jhb
Differential Revision:  https://reviews.freebsd.org/D35623
Sponsored by:           Beckhoff Automation GmbH & Co. KG
This commit is contained in:
Corvin Köhne 2022-09-07 09:07:03 +02:00 committed by Emmanuel Vadot
parent a974702e27
commit 0bda8d3e9f
9 changed files with 199 additions and 71 deletions
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8
sys/amd64/include/vmm.h
View file

@ -31,6 +31,7 @@
#ifndef _VMM_H_
#define _VMM_H_
#include <sys/cpuset.h>
#include <sys/sdt.h>
#include <x86/segments.h>
@ -483,6 +484,7 @@ enum vm_cap_type {
VM_CAP_BPT_EXIT,
VM_CAP_RDPID,
VM_CAP_RDTSCP,
VM_CAP_IPI_EXIT,
VM_CAP_MAX
};
@ -630,6 +632,7 @@ enum vm_exitcode {
VM_EXITCODE_DEBUG,
VM_EXITCODE_VMINSN,
VM_EXITCODE_BPT,
VM_EXITCODE_IPI,
VM_EXITCODE_MAX
};
@ -737,6 +740,11 @@ struct vm_exit {
struct {
enum vm_suspend_how how;
} suspended;
struct {
uint32_t mode;
uint8_t vector;
cpuset_t dmask;
} ipi;
struct vm_task_switch task_switch;
} u;
};

10
sys/amd64/vmm/amd/svm.c
View file

@ -2315,6 +2315,7 @@ static int
svm_setcap(void *arg, int vcpu, int type, int val)
{
struct svm_softc *sc;
struct vlapic *vlapic;
int error;
sc = arg;
@ -2333,6 +2334,10 @@ svm_setcap(void *arg, int vcpu, int type, int val)
if (val == 0)
error = EINVAL;
break;
case VM_CAP_IPI_EXIT:
vlapic = vm_lapic(sc->vm, vcpu);
vlapic->ipi_exit = val;
break;
default:
error = ENOENT;
break;
@ -2344,6 +2349,7 @@ static int
svm_getcap(void *arg, int vcpu, int type, int *retval)
{
struct svm_softc *sc;
struct vlapic *vlapic;
int error;
sc = arg;
@ -2361,6 +2367,10 @@ svm_getcap(void *arg, int vcpu, int type, int *retval)
case VM_CAP_UNRESTRICTED_GUEST:
*retval = 1; /* unrestricted guest is always enabled */
break;
case VM_CAP_IPI_EXIT:
vlapic = vm_lapic(sc->vm, vcpu);
*retval = vlapic->ipi_exit;
break;
default:
error = ENOENT;
break;

8
sys/amd64/vmm/intel/vmx.c
View file

@ -3504,6 +3504,7 @@ vmx_getcap(void *arg, int vcpu, int type, int *retval)
ret = 0;
break;
case VM_CAP_BPT_EXIT:
case VM_CAP_IPI_EXIT:
ret = 0;
break;
default:
@ -3521,6 +3522,7 @@ vmx_setcap(void *arg, int vcpu, int type, int val)
{
struct vmx *vmx = arg;
struct vmcs *vmcs = &vmx->vmcs[vcpu];
struct vlapic *vlapic;
uint32_t baseval;
uint32_t *pptr;
int error;
@ -3599,6 +3601,12 @@ vmx_setcap(void *arg, int vcpu, int type, int val)
reg = VMCS_EXCEPTION_BITMAP;
}
break;
case VM_CAP_IPI_EXIT:
retval = 0;
vlapic = vm_lapic(vmx->vm, vcpu);
vlapic->ipi_exit = val;
break;
default:
break;
}

194
sys/amd64/vmm/io/vlapic.c
View file

@ -84,6 +84,7 @@ __FBSDID("$FreeBSD$");
static void vlapic_set_error(struct vlapic *, uint32_t, bool);
static void vlapic_callout_handler(void *arg);
static void vlapic_reset(struct vlapic *vlapic);
static __inline uint32_t
vlapic_get_id(struct vlapic *vlapic)
@ -957,13 +958,12 @@ vlapic_icrlo_write_handler(struct vlapic *vlapic, bool *retu)
{
int i;
bool phys;
cpuset_t dmask;
cpuset_t dmask, ipimask;
uint64_t icrval;
uint32_t dest, vec, mode;
uint32_t dest, vec, mode, shorthand;
struct vlapic *vlapic2;
struct vm_exit *vmexit;
struct LAPIC *lapic;
uint16_t maxcpus;
lapic = vlapic->apic_page;
lapic->icr_lo &= ~APIC_DELSTAT_PEND;
@ -975,97 +975,147 @@ vlapic_icrlo_write_handler(struct vlapic *vlapic, bool *retu)
dest = icrval >> (32 + 24);
vec = icrval & APIC_VECTOR_MASK;
mode = icrval & APIC_DELMODE_MASK;
if (mode == APIC_DELMODE_FIXED && vec < 16) {
vlapic_set_error(vlapic, APIC_ESR_SEND_ILLEGAL_VECTOR, false);
VLAPIC_CTR1(vlapic, "Ignoring invalid IPI %d", vec);
return (0);
}
phys = (icrval & APIC_DESTMODE_LOG) == 0;
shorthand = icrval & APIC_DEST_MASK;
VLAPIC_CTR2(vlapic, "icrlo 0x%016lx triggered ipi %d", icrval, vec);
if (mode == APIC_DELMODE_FIXED || mode == APIC_DELMODE_NMI) {
switch (icrval & APIC_DEST_MASK) {
case APIC_DEST_DESTFLD:
phys = ((icrval & APIC_DESTMODE_LOG) == 0);
vlapic_calcdest(vlapic->vm, &dmask, dest, phys, false,
x2apic(vlapic));
break;
case APIC_DEST_SELF:
CPU_SETOF(vlapic->vcpuid, &dmask);
break;
case APIC_DEST_ALLISELF:
dmask = vm_active_cpus(vlapic->vm);
break;
case APIC_DEST_ALLESELF:
dmask = vm_active_cpus(vlapic->vm);
CPU_CLR(vlapic->vcpuid, &dmask);
break;
default:
CPU_ZERO(&dmask); /* satisfy gcc */
break;
switch (shorthand) {
case APIC_DEST_DESTFLD:
vlapic_calcdest(vlapic->vm, &dmask, dest, phys, false, x2apic(vlapic));
break;
case APIC_DEST_SELF:
CPU_SETOF(vlapic->vcpuid, &dmask);
break;
case APIC_DEST_ALLISELF:
dmask = vm_active_cpus(vlapic->vm);
break;
case APIC_DEST_ALLESELF:
dmask = vm_active_cpus(vlapic->vm);
CPU_CLR(vlapic->vcpuid, &dmask);
break;
default:
__assert_unreachable();
}
/*
* ipimask is a set of vCPUs needing userland handling of the current
* IPI.
*/
CPU_ZERO(&ipimask);
switch (mode) {
case APIC_DELMODE_FIXED:
if (vec < 16) {
vlapic_set_error(vlapic, APIC_ESR_SEND_ILLEGAL_VECTOR,
false);
VLAPIC_CTR1(vlapic, "Ignoring invalid IPI %d", vec);
return (0);
}
CPU_FOREACH_ISSET(i, &dmask) {
if (mode == APIC_DELMODE_FIXED) {
lapic_intr_edge(vlapic->vm, i, vec);
vmm_stat_array_incr(vlapic->vm, vlapic->vcpuid,
IPIS_SENT, i, 1);
VLAPIC_CTR2(vlapic, "vlapic sending ipi %d "
"to vcpuid %d", vec, i);
} else {
vm_inject_nmi(vlapic->vm, i);
VLAPIC_CTR1(vlapic, "vlapic sending ipi nmi "
"to vcpuid %d", i);
}
lapic_intr_edge(vlapic->vm, i, vec);
vmm_stat_array_incr(vlapic->vm, vlapic->vcpuid,
IPIS_SENT, i, 1);
VLAPIC_CTR2(vlapic,
"vlapic sending ipi %d to vcpuid %d", vec, i);
}
return (0); /* handled completely in the kernel */
}
break;
case APIC_DELMODE_NMI:
CPU_FOREACH_ISSET(i, &dmask) {
vm_inject_nmi(vlapic->vm, i);
VLAPIC_CTR1(vlapic,
"vlapic sending ipi nmi to vcpuid %d", i);
}
maxcpus = vm_get_maxcpus(vlapic->vm);
if (mode == APIC_DELMODE_INIT) {
break;
case APIC_DELMODE_INIT:
if ((icrval & APIC_LEVEL_MASK) == APIC_LEVEL_DEASSERT)
return (0);
break;
if (vlapic->vcpuid == 0 && dest != 0 && dest < maxcpus) {
vlapic2 = vm_lapic(vlapic->vm, dest);
/* move from INIT to waiting-for-SIPI state */
if (vlapic2->boot_state == BS_INIT) {
vlapic2->boot_state = BS_SIPI;
}
return (0);
CPU_FOREACH_ISSET(i, &dmask) {
/*
* Userland which doesn't support the IPI exit requires
* that the boot state is set to SIPI here.
*/
vlapic2 = vm_lapic(vlapic->vm, i);
vlapic2->boot_state = BS_SIPI;
CPU_SET(i, &ipimask);
}
}
if (mode == APIC_DELMODE_STARTUP) {
if (vlapic->vcpuid == 0 && dest != 0 && dest < maxcpus) {
vlapic2 = vm_lapic(vlapic->vm, dest);
break;
case APIC_DELMODE_STARTUP:
CPU_FOREACH_ISSET(i, &dmask) {
vlapic2 = vm_lapic(vlapic->vm, i);
/*
* Ignore SIPIs in any state other than wait-for-SIPI
*/
if (vlapic2->boot_state != BS_SIPI)
return (0);
continue;
vlapic2->boot_state = BS_RUNNING;
CPU_SET(i, &ipimask);
}
*retu = true;
vmexit = vm_exitinfo(vlapic->vm, vlapic->vcpuid);
vmexit->exitcode = VM_EXITCODE_SPINUP_AP;
vmexit->u.spinup_ap.vcpu = dest;
vmexit->u.spinup_ap.rip = vec << PAGE_SHIFT;
break;
default:
return (1);
}
return (0);
if (!CPU_EMPTY(&ipimask)) {
vmexit = vm_exitinfo(vlapic->vm, vlapic->vcpuid);
vmexit->exitcode = VM_EXITCODE_IPI;
vmexit->u.ipi.mode = mode;
vmexit->u.ipi.vector = vec;
vmexit->u.ipi.dmask = dmask;
*retu = true;
/*
* Old bhyve versions don't support the IPI exit. Translate it
* into the old style.
*/
if (!vlapic->ipi_exit) {
if (mode == APIC_DELMODE_STARTUP) {
vmexit->exitcode = VM_EXITCODE_SPINUP_AP;
vmexit->u.spinup_ap.vcpu = CPU_FFS(&ipimask) - 1;
vmexit->u.spinup_ap.rip = vec << PAGE_SHIFT;
} else {
*retu = false;
}
}
}
/*
* This will cause a return to userland.
*/
return (1);
return (0);
}
static void
vlapic_handle_init(struct vm *vm, int vcpuid, void *arg)
{
struct vlapic *vlapic = vm_lapic(vm, vcpuid);
vlapic_reset(vlapic);
/* vlapic_reset modifies the boot state. */
vlapic->boot_state = BS_SIPI;
}
int
vm_handle_ipi(struct vm *vm, int vcpuid, struct vm_exit *vme, bool *retu)
{
*retu = true;
switch (vme->u.ipi.mode) {
case APIC_DELMODE_INIT:
vm_smp_rendezvous(vm, vcpuid, vme->u.ipi.dmask,
vlapic_handle_init, NULL);
break;
case APIC_DELMODE_STARTUP:
break;
default:
return (1);
}
return (0);
}
void
@ -1467,6 +1517,8 @@ vlapic_init(struct vlapic *vlapic)
if (vlapic->vcpuid == 0)
vlapic->msr_apicbase |= APICBASE_BSP;
vlapic->ipi_exit = false;
vlapic_reset(vlapic);
}

2
sys/amd64/vmm/io/vlapic.h
View file

@ -115,4 +115,6 @@ void vlapic_self_ipi_handler(struct vlapic *vlapic, uint64_t val);
int vlapic_snapshot(struct vm *vm, struct vm_snapshot_meta *meta);
#endif
int vm_handle_ipi(struct vm *vm, int vcpuid, struct vm_exit *vme, bool *retu);
#endif /* _VLAPIC_H_ */

2
sys/amd64/vmm/io/vlapic_priv.h
View file

@ -183,6 +183,8 @@ struct vlapic {
*/
uint32_t svr_last;
uint32_t lvt_last[VLAPIC_MAXLVT_INDEX + 1];
bool ipi_exit;
};
void vlapic_init(struct vlapic *vlapic);

9
sys/amd64/vmm/vmm.c
View file

@ -1818,6 +1818,15 @@ vm_run(struct vm *vm, struct vm_run *vmrun)
}
}
/*
* VM_EXITCODE_INST_EMUL could access the apic which could transform the
* exit code into VM_EXITCODE_IPI.
*/
if (error == 0 && vme->exitcode == VM_EXITCODE_IPI) {
retu = false;
error = vm_handle_ipi(vm, vcpuid, vme, &retu);
}
if (error == 0 && retu == false)
goto restart;

34
usr.sbin/bhyve/bhyverun.c
View file

@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
#endif
#include <amd64/vmm/intel/vmcs.h>
#include <x86/apicreg.h>
#include <machine/atomic.h>
#include <machine/segments.h>
@ -939,6 +940,35 @@ vmexit_breakpoint(struct vmctx *ctx __unused, struct vm_exit *vme, int *pvcpu)
return (VMEXIT_CONTINUE);
}
static int
vmexit_ipi(struct vmctx *ctx, struct vm_exit *vmexit, int *pvcpu)
{
int error = -1;
int i;
switch (vmexit->u.ipi.mode) {
case APIC_DELMODE_INIT:
CPU_FOREACH_ISSET (i, &vmexit->u.ipi.dmask) {
error = vm_suspend_cpu(ctx, i);
if (error) {
warnx("%s: failed to suspend cpu %d\n",
__func__, i);
break;
}
}
break;
case APIC_DELMODE_STARTUP:
CPU_FOREACH_ISSET (i, &vmexit->u.ipi.dmask) {
spinup_ap(ctx, i, vmexit->u.ipi.vector << PAGE_SHIFT);
}
error = 0;
break;
default:
break;
}
return (error);
}
static vmexit_handler_t handler[VM_EXITCODE_MAX] = {
[VM_EXITCODE_INOUT] = vmexit_inout,
[VM_EXITCODE_INOUT_STR] = vmexit_inout,
@ -955,6 +985,7 @@ static vmexit_handler_t handler[VM_EXITCODE_MAX] = {
[VM_EXITCODE_TASK_SWITCH] = vmexit_task_switch,
[VM_EXITCODE_DEBUG] = vmexit_debug,
[VM_EXITCODE_BPT] = vmexit_breakpoint,
[VM_EXITCODE_IPI] = vmexit_ipi,
};
static void
@ -1155,6 +1186,9 @@ spinup_vcpu(struct vmctx *ctx, int vcpu, bool suspend)
error = vm_set_capability(ctx, vcpu, VM_CAP_UNRESTRICTED_GUEST, 1);
assert(error == 0);
error = vm_set_capability(ctx, vcpu, VM_CAP_IPI_EXIT, 1);
assert(error == 0);
fbsdrun_addcpu(ctx, vcpu, rip, suspend);
}

3
usr.sbin/bhyve/spinup_ap.c
View file

@ -98,6 +98,9 @@ spinup_ap(struct vmctx *ctx, int newcpu, uint64_t rip)
error = vm_set_capability(ctx, newcpu, VM_CAP_UNRESTRICTED_GUEST, 1);
assert(error == 0);
error = vm_set_capability(ctx, newcpu, VM_CAP_IPI_EXIT, 1);
assert(error == 0);
spinup_ap_realmode(ctx, newcpu, &rip);
vm_resume_cpu(ctx, newcpu);