On 10/16/24 22:05, Sean Christopherson wrote:
On Tue, Oct 15, 2024, Ivan Orlov wrote:
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c67e448c6ebd..afd785e7f3a3 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6550,19 +6550,10 @@ static int __vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
exit_reason.basic != EXIT_REASON_APIC_ACCESS &&
exit_reason.basic != EXIT_REASON_TASK_SWITCH &&
exit_reason.basic != EXIT_REASON_NOTIFY)) {
- int ndata = 3;
+ gpa_t gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
+ bool is_mmio = exit_reason.basic == EXIT_REASON_EPT_MISCONFIG;
There's no need for is_mmio, just pass INVALID_GPA when the GPA isn't known.
Ah alright, then we definitely don't need an is_mmio field. I assume we
can't do MMIO at GPA=0, right?
Wrong :-)
Then getting rid of `is_mmio` will make distinguishing between vectoring
error due to MMIO with GPA=0 and non-mmio vectoring error quite hard for
the error reporti
Passing INVALID_GPA into the userspace due to non-mmio vectoring error
will change the existing internal.data order, but I can do it if it's
fine. Sorry for nitpicking :)
From an architectural perspective, GPA=0 is not special in any way. E.g. prior
to L1TF, Linux would happily use the page with PFN=0.
Cool, didn't know about this vulnerability... Thanks for the explanation!
--
Kind regards,
Ivan Orlov
