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KVM: nVMX: Free only guest_mode (L2) roots on INVVPID w/o EPT

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When emulating INVVPID for L1, free only L2+ roots, using the guest_mode
tag in the MMU role to identify L2+ roots.  From L1's perspective, its
own TLB entries use VPID=0, and INVVPID is not requied to invalidate such
entries.  Per Intel's SDM, INVVPID _may_ invalidate entries with VPID=0,
but it is not required to do so.

Cc: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-06-09 16:42:29 -07:00 committed by Paolo Bonzini
parent 50a417962a
commit 25b62c6274
3 changed files with 31 additions and 4 deletions
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1
arch/x86/include/asm/kvm_host.h
View File

@ -1684,6 +1684,7 @@ int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn);
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
ulong roots_to_free);
void kvm_mmu_free_guest_mode_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu);
gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access,
struct x86_exception *exception);
gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva,

27
arch/x86/kvm/mmu/mmu.c
View File

@ -3212,6 +3212,33 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
}
EXPORT_SYMBOL_GPL(kvm_mmu_free_roots);
void kvm_mmu_free_guest_mode_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
{
unsigned long roots_to_free = 0;
hpa_t root_hpa;
int i;
/*
* This should not be called while L2 is active, L2 can't invalidate
* _only_ its own roots, e.g. INVVPID unconditionally exits.
*/
WARN_ON_ONCE(mmu->mmu_role.base.guest_mode);
for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
root_hpa = mmu->prev_roots[i].hpa;
if (!VALID_PAGE(root_hpa))
continue;
if (!to_shadow_page(root_hpa) ||
to_shadow_page(root_hpa)->role.guest_mode)
roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
}
kvm_mmu_free_roots(vcpu, mmu, roots_to_free);
}
EXPORT_SYMBOL_GPL(kvm_mmu_free_guest_mode_roots);
static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn)
{
int ret = 0;

7
arch/x86/kvm/vmx/nested.c
View File

@ -5481,8 +5481,8 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
/*
* Sync the shadow page tables if EPT is disabled, L1 is invalidating
* linear mappings for L2 (tagged with L2's VPID). Free all roots as
* VPIDs are not tracked in the MMU role.
* linear mappings for L2 (tagged with L2's VPID). Free all guest
* roots as VPIDs are not tracked in the MMU role.
*
* Note, this operates on root_mmu, not guest_mmu, as L1 and L2 share
* an MMU when EPT is disabled.
@ -5490,8 +5490,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
* TODO: sync only the affected SPTEs for INVDIVIDUAL_ADDR.
*/
if (!enable_ept)
kvm_mmu_free_roots(vcpu, &vcpu->arch.root_mmu,
KVM_MMU_ROOTS_ALL);
kvm_mmu_free_guest_mode_roots(vcpu, &vcpu->arch.root_mmu);
return nested_vmx_succeed(vcpu);
}