On 30.03.23 22:15, Mathias Krause wrote:
> [...]
> Maybe it's not a stale CR0 value but the page table walker not taking
> the guest's CR0.WP into account? Maybe a missing role update?
Indeed, it is. This does the trick for me:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 31be188aa842..6a9e90725c84 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8372,6 +8372,9 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
init_decode_cache(ctxt);
vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
+ /* Ensure we're doing page table walks with an up2date MMU role */
+ if ((vcpu->arch.cr0 ^ kvm_read_cr0(vcpu)) == X86_CR0_WP)
+ kvm_init_mmu(vcpu);
}
void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
Very heavy weight and misplaced, but a start :)
It should (1) be limited to VMX as that's the only one that would make
CR0.WP a guest owned bit and (2) limited to emulated instructions that
actually do write operations, as read are harmless, obviously.
Mathias
