[PATCH v2 07/22] KVM: x86: Store gpa as gpa_t, not unsigned long, when unprotecting for retry

From: Sean Christopherson
Date: Fri Aug 30 2024 - 20:17:52 EST


Store the gpa used to unprotect the faulting gfn for retry as a gpa_t, not
an unsigned long. This fixes a bug where 32-bit KVM would unprotect and
retry the wrong gfn if the gpa had bits 63:32!=0. In practice, this bug
is functionally benign, as unprotecting the wrong gfn is purely a
performance issue (thanks to the anti-infinite-loop logic). And of course,
almost no one runs 32-bit KVM these days.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a1f0f4dede55..c84f57e1a888 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8928,7 +8928,8 @@ static bool retry_instruction(struct x86_emulate_ctxt *ctxt,
gpa_t cr2_or_gpa, int emulation_type)
{
struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
- unsigned long last_retry_eip, last_retry_addr, gpa = cr2_or_gpa;
+ unsigned long last_retry_eip, last_retry_addr;
+ gpa_t gpa = cr2_or_gpa;

last_retry_eip = vcpu->arch.last_retry_eip;
last_retry_addr = vcpu->arch.last_retry_addr;
--
2.46.0.469.g59c65b2a67-goog