leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

KVM: SVM: always update CR3 in VMCB

Browse Source 
svm_load_mmu_pgd is delaying the write of GUEST_CR3 to prepare_vmcs02 as
an optimization, but this is only correct before the nested vmentry.
If userspace is modifying CR3 with KVM_SET_SREGS after the VM has
already been put in guest mode, the value of CR3 will not be updated.
Remove the optimization, which almost never triggers anyway.
This was was added in commit 689f3bf216 ("KVM: x86: unify callbacks
to load paging root", 2020-03-16) just to keep the two vendor-specific
modules closer, but we'll fix VMX too.

Fixes: 689f3bf216 ("KVM: x86: unify callbacks to load paging root")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
2020-05-20 08:37:37 -04:00
parent 5b67240866
commit 978ce5837c
2 changed files with 6 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/kvm/svm/nested.c
View File

@@ -256,11 +256,7 @@ void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
svm_set_efer(&svm->vcpu, nested_vmcb->save.efer);
svm_set_cr0(&svm->vcpu, nested_vmcb->save.cr0);
svm_set_cr4(&svm->vcpu, nested_vmcb->save.cr4);
if (npt_enabled) {
svm->vmcb->save.cr3 = nested_vmcb->save.cr3;
svm->vcpu.arch.cr3 = nested_vmcb->save.cr3;
} else
(void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
(void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
/* Guest paging mode is active - reset mmu */
kvm_mmu_reset_context(&svm->vcpu);