diff options
| author |   Sean Christopherson <seanjc@google.com> | 2024-08-02 13:39:00 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-08-29 19:05:55 -0700 |
| commit | 1dc9cc1c4c230fbc6bf6322f150d4b81f712cfb9 (patch) | |
| tree | 7ec2b1f680dff853eb628a2c805774a50fc7dbab | |
| parent | KVM: x86/mmu: Drop pointless "return" wrapper label in FNAME(fetch) (diff) | |
| download | wireguard-linux-1dc9cc1c4c230fbc6bf6322f150d4b81f712cfb9.tar.xz wireguard-linux-1dc9cc1c4c230fbc6bf6322f150d4b81f712cfb9.zip | |
KVM: x86/mmu: Reword a misleading comment about checking gpte_changed()
Rewrite the comment in FNAME(fetch) to explain why KVM needs to check that
the gPTE is still fresh before continuing the shadow page walk, even if
KVM already has a linked shadow page for the gPTE in question.
No functional change intended.
Link: https://lore.kernel.org/r/20240802203900.348808-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/mmu/paging_tmpl.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 480c54122991..405bd7ceee2a 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -695,8 +695,14 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, return RET_PF_RETRY; /* - * Verify that the gpte in the page we've just write - * protected is still there. + * Verify that the gpte in the page, which is now either + * write-protected or unsync, wasn't modified between the fault + * and acquiring mmu_lock. This needs to be done even when + * reusing an existing shadow page to ensure the information + * gathered by the walker matches the information stored in the + * shadow page (which could have been modified by a different + * vCPU even if the page was already linked). Holding mmu_lock + * prevents the shadow page from changing after this point. */ if (FNAME(gpte_changed)(vcpu, gw, it.level - 1)) return RET_PF_RETRY; |