system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-09-06 09:51:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

KVM: VMX: Introduce test mode related to EPT violation VE

Browse source 
To support TDX, KVM is enhanced to operate with #VE.  For TDX, KVM uses the
suppress #VE bit in EPT entries selectively, in order to be able to trap
non-present conditions.  However, #VE isn't used for VMX and it's a bug
if it happens.  To be defensive and test that VMX case isn't broken
introduce an option ept_violation_ve_test and when it's set, BUG the vm.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-Id: <d6db6ba836605c0412e166359ba5c46a63c22f86.1705965635.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Isaku Yamahata 2024-01-22 15:53:18 -08:00 committed by Paolo Bonzini
parent fb29541ead
commit 8131cf5b4f
4 changed files with 73 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
arch/x86/kvm/Kconfig
View file

@ -95,6 +95,19 @@ config KVM_INTEL
To compile this as a module, choose M here: the module
will be called kvm-intel.
config KVM_INTEL_PROVE_VE
bool "Check that guests do not receive #VE exceptions"
default KVM_PROVE_MMU || DEBUG_KERNEL
depends on KVM_INTEL
help
Checks that KVM's page table management code will not incorrectly
let guests receive a virtualization exception. Virtualization
exceptions will be trapped by the hypervisor rather than injected
in the guest.
If unsure, say N.
config X86_SGX_KVM
bool "Software Guard eXtensions (SGX) Virtualization"
depends on X86_SGX && KVM_INTEL

5
arch/x86/kvm/vmx/vmcs.h
View file

@ -140,6 +140,11 @@ static inline bool is_nm_fault(u32 intr_info)
return is_exception_n(intr_info, NM_VECTOR);
}
static inline bool is_ve_fault(u32 intr_info)
{
return is_exception_n(intr_info, VE_VECTOR);
}
/* Undocumented: icebp/int1 */
static inline bool is_icebp(u32 intr_info)
{

53
arch/x86/kvm/vmx/vmx.c
View file

@ -869,6 +869,12 @@ void vmx_update_exception_bitmap(struct kvm_vcpu *vcpu)
eb = (1u << PF_VECTOR) | (1u << UD_VECTOR) | (1u << MC_VECTOR) |
(1u << DB_VECTOR) | (1u << AC_VECTOR);
/*
* #VE isn't used for VMX. To test against unexpected changes
* related to #VE for VMX, intercept unexpected #VE and warn on it.
*/
if (IS_ENABLED(CONFIG_KVM_INTEL_PROVE_VE))
eb |= 1u << VE_VECTOR;
/*
* Guest access to VMware backdoor ports could legitimately
* trigger #GP because of TSS I/O permission bitmap.
@ -2602,6 +2608,9 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
&_cpu_based_2nd_exec_control))
return -EIO;
}
if (!IS_ENABLED(CONFIG_KVM_INTEL_PROVE_VE))
_cpu_based_2nd_exec_control &= ~SECONDARY_EXEC_EPT_VIOLATION_VE;
#ifndef CONFIG_X86_64
if (!(_cpu_based_2nd_exec_control &
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES))
@ -2626,6 +2635,7 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
return -EIO;
vmx_cap->ept = 0;
_cpu_based_2nd_exec_control &= ~SECONDARY_EXEC_EPT_VIOLATION_VE;
}
if (!(_cpu_based_2nd_exec_control & SECONDARY_EXEC_ENABLE_VPID) &&
vmx_cap->vpid) {
@ -4588,6 +4598,7 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx)
exec_control &= ~SECONDARY_EXEC_ENABLE_VPID;
if (!enable_ept) {
exec_control &= ~SECONDARY_EXEC_ENABLE_EPT;
exec_control &= ~SECONDARY_EXEC_EPT_VIOLATION_VE;
enable_unrestricted_guest = 0;
}
if (!enable_unrestricted_guest)
@ -4711,8 +4722,12 @@ static void init_vmcs(struct vcpu_vmx *vmx)
exec_controls_set(vmx, vmx_exec_control(vmx));
if (cpu_has_secondary_exec_ctrls())
if (cpu_has_secondary_exec_ctrls()) {
secondary_exec_controls_set(vmx, vmx_secondary_exec_control(vmx));
if (vmx->ve_info)
vmcs_write64(VE_INFORMATION_ADDRESS,
__pa(vmx->ve_info));
}
if (cpu_has_tertiary_exec_ctrls())
tertiary_exec_controls_set(vmx, vmx_tertiary_exec_control(vmx));
@ -5200,6 +5215,9 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
if (is_invalid_opcode(intr_info))
return handle_ud(vcpu);
if (KVM_BUG_ON(is_ve_fault(intr_info), vcpu->kvm))
return -EIO;
error_code = 0;
if (intr_info & INTR_INFO_DELIVER_CODE_MASK)
error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
@ -6409,8 +6427,22 @@ void dump_vmcs(struct kvm_vcpu *vcpu)
pr_err("Virtual processor ID = 0x%04x\n",
vmcs_read16(VIRTUAL_PROCESSOR_ID));
if (secondary_exec_control & SECONDARY_EXEC_EPT_VIOLATION_VE) {
pr_err("VE info address = 0x%016llx\n",
vmcs_read64(VE_INFORMATION_ADDRESS));
struct vmx_ve_information *ve_info = vmx->ve_info;
u64 ve_info_pa = vmcs_read64(VE_INFORMATION_ADDRESS);
/*
* If KVM is dumping the VMCS, then something has gone wrong
* already. Derefencing an address from the VMCS, which could
* very well be corrupted, is a terrible idea. The virtual
* address is known so use it.
*/
pr_err("VE info address = 0x%016llx%s\n", ve_info_pa,
ve_info_pa == __pa(ve_info) ? "" : "(corrupted!)");
pr_err("ve_info: 0x%08x 0x%08x 0x%016llx 0x%016llx 0x%016llx 0x%04x\n",
ve_info->exit_reason, ve_info->delivery,
ve_info->exit_qualification,
ve_info->guest_linear_address,
ve_info->guest_physical_address, ve_info->eptp_index);
}
}
@ -7466,6 +7498,7 @@ void vmx_vcpu_free(struct kvm_vcpu *vcpu)
free_vpid(vmx->vpid);
nested_vmx_free_vcpu(vcpu);
free_loaded_vmcs(vmx->loaded_vmcs);
free_page((unsigned long)vmx->ve_info);
}
int vmx_vcpu_create(struct kvm_vcpu *vcpu)
@ -7559,6 +7592,20 @@ int vmx_vcpu_create(struct kvm_vcpu *vcpu)
goto free_vmcs;
}
err = -ENOMEM;
if (vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_EPT_VIOLATION_VE) {
struct page *page;
BUILD_BUG_ON(sizeof(*vmx->ve_info) > PAGE_SIZE);
/* ve_info must be page aligned. */
page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
if (!page)
goto free_vmcs;
vmx->ve_info = page_to_virt(page);
}
if (vmx_can_use_ipiv(vcpu))
WRITE_ONCE(to_kvm_vmx(vcpu->kvm)->pid_table[vcpu->vcpu_id],
__pa(&vmx->pi_desc) | PID_TABLE_ENTRY_VALID);

6
arch/x86/kvm/vmx/vmx.h
View file

@ -362,6 +362,9 @@ struct vcpu_vmx {
DECLARE_BITMAP(read, MAX_POSSIBLE_PASSTHROUGH_MSRS);
DECLARE_BITMAP(write, MAX_POSSIBLE_PASSTHROUGH_MSRS);
} shadow_msr_intercept;
/* ve_info must be page aligned. */
struct vmx_ve_information *ve_info;
};
struct kvm_vmx {
@ -574,7 +577,8 @@ static inline u8 vmx_get_rvi(void)
SECONDARY_EXEC_ENABLE_VMFUNC | \
SECONDARY_EXEC_BUS_LOCK_DETECTION | \
SECONDARY_EXEC_NOTIFY_VM_EXITING | \
SECONDARY_EXEC_ENCLS_EXITING)
SECONDARY_EXEC_ENCLS_EXITING | \
SECONDARY_EXEC_EPT_VIOLATION_VE)
#define KVM_REQUIRED_VMX_TERTIARY_VM_EXEC_CONTROL 0
#define KVM_OPTIONAL_VMX_TERTIARY_VM_EXEC_CONTROL \