Re: [PATCH v6 2/7] KVM: VMX: Use is_64_bit_mode() to check 64-bit mode

[Chao Gao <chao.gao@intel.com>]

On Sun, Mar 19, 2023 at 04:49:22PM +0800, Binbin Wu wrote:
>get_vmx_mem_address() and sgx_get_encls_gva() use is_long_mode()
>to check 64-bit mode. Should use is_64_bit_mode() instead.
>
>Fixes: f9eb4af67c9d ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions")
>Fixes: 70210c044b4e ("KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions")

It is better to split this patch into two: one for nested and one for
SGX.

It is possible that there is a kernel release which has just one of
above two flawed commits, then this fix patch cannot be applied cleanly
to the release.

>Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
>---
> arch/x86/kvm/vmx/nested.c | 2 +-
> arch/x86/kvm/vmx/sgx.c    | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
>diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>index 557b9c468734..0f84cc05f57c 100644
>--- a/arch/x86/kvm/vmx/nested.c
>+++ b/arch/x86/kvm/vmx/nested.c
>@@ -4959,7 +4959,7 @@ int get_vmx_mem_address(struct kvm_vcpu *vcpu, unsigned long exit_qualification,
> 
> 	/* Checks for #GP/#SS exceptions. */
> 	exn = false;
>-	if (is_long_mode(vcpu)) {
>+	if (is_64_bit_mode(vcpu)) {
> 		/*
> 		 * The virtual/linear address is never truncated in 64-bit
> 		 * mode, e.g. a 32-bit address size can yield a 64-bit virtual
>diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
>index aa53c98034bf..0574030b071f 100644
>--- a/arch/x86/kvm/vmx/sgx.c
>+++ b/arch/x86/kvm/vmx/sgx.c
>@@ -29,14 +29,14 @@ static int sgx_get_encls_gva(struct kvm_vcpu *vcpu, unsigned long offset,
> 
> 	/* Skip vmcs.GUEST_DS retrieval for 64-bit mode to avoid VMREADs. */
> 	*gva = offset;
>-	if (!is_long_mode(vcpu)) {
>+	if (!is_64_bit_mode(vcpu)) {
> 		vmx_get_segment(vcpu, &s, VCPU_SREG_DS);
> 		*gva += s.base;
> 	}
> 
> 	if (!IS_ALIGNED(*gva, alignment)) {
> 		fault = true;
>-	} else if (likely(is_long_mode(vcpu))) {
>+	} else if (likely(is_64_bit_mode(vcpu))) {
> 		fault = is_noncanonical_address(*gva, vcpu);
> 	} else {
> 		*gva &= 0xffffffff;
>-- 
>2.25.1
>