[PATCH v2 01/15] KVM: SVM: Truncate INVLPGA address in compatibility mode

[Sean Christopherson <seanjc@google.com>]

Check for full 64-bit mode, not just long mode, when truncating the
virtual address as part of INVLPGA emulation.  Compatibility mode doesn't
support 64-bit addressing.

Note, the FIXME still applies, e.g. if the guest deliberately targeted
EAX while in 64-bit via an address size override.  That flaw isn't worth
fixing as it would require decoding the code stream, which would open a
an entirely different can of worms, and in practice no sane guest would
shove garbage into RAX[63:32] and execute INVLPGA.

Note #2, VMSAVE, VMLOAD, and VMRUN all suffer from the same architectural
flaw of not providing the full linear address in a VMCB exit information
field, because, quoting the APM verbatim:

  the linear address is available directly from the guest rAX register

(VMSAVE, VMLOAD, and VMRUN take a physical address, but they're behavior
with respect to rAX is otherwise identical).

Fixes: bc9eff67fc35 ("KVM: SVM: Use default rAX size for INVLPGA emulation")
Reviewed-by: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/svm/svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e74fcde6155e..4ad87f8df392 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2415,7 +2415,7 @@ static int invlpga_interception(struct kvm_vcpu *vcpu)
 		return 1;
 
 	/* FIXME: Handle an address size prefix. */
-	if (!is_long_mode(vcpu))
+	if (!is_64_bit_mode(vcpu))
 		gva = (u32)gva;
 
 	trace_kvm_invlpga(to_svm(vcpu)->vmcb->save.rip, asid, gva);
-- 
2.54.0.563.g4f69b47b94-goog