[PATCH 04/11] KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode

Sean Christopherson
2026-04-09T23:56:36Z

When getting register values for ENCLS emulation, use kvm_register_read()
instead of kvm_<reg>_read() so that bits 63:32 of the register are dropped
if the guest is in 32-bit mode.

Note, the misleading/surprising behavior of kvm_<reg>_read() being "raw"
variants under the hood will be addressed once all non-benign bugs are
fixed.

Fixes: 70210c044b4e ("KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions")
Fixes: b6f084ca5538 ("KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC)")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/sgx.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index df1d0cf76947..4c61fc33f764 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -225,8 +225,8 @@ static int handle_encls_ecreate(struct kvm_vcpu *vcpu)
struct x86_exception ex;
int r;

- if (sgx_get_encls_gva(vcpu, kvm_rbx_read(vcpu), 32, 32, &pageinfo_gva) ||
- sgx_get_encls_gva(vcpu, kvm_rcx_read(vcpu), 4096, 4096, &secs_gva))
+ if (sgx_get_encls_gva(vcpu, kvm_register_read(vcpu, VCPU_REGS_RBX), 32, 32, &pageinfo_gva) ||
+ sgx_get_encls_gva(vcpu, kvm_register_read(vcpu, VCPU_REGS_RCX), 4096, 4096, &secs_gva))
return 1;

/*
@@ -302,9 +302,9 @@ static int handle_encls_einit(struct kvm_vcpu *vcpu)
gpa_t sig_gpa, secs_gpa, token_gpa;
int ret, trapnr;

- if (sgx_get_encls_gva(vcpu, kvm_rbx_read(vcpu), 1808, 4096, &sig_gva) ||
- sgx_get_encls_gva(vcpu, kvm_rcx_read(vcpu), 4096, 4096, &secs_gva) ||
- sgx_get_encls_gva(vcpu, kvm_rdx_read(vcpu), 304, 512, &token_gva))
+ if (sgx_get_encls_gva(vcpu, kvm_register_read(vcpu, VCPU_REGS_RBX), 1808, 4096, &sig_gva) ||
+ sgx_get_encls_gva(vcpu, kvm_register_read(vcpu, VCPU_REGS_RCX), 4096, 4096, &secs_gva) ||
+ sgx_get_encls_gva(vcpu, kvm_register_read(vcpu, VCPU_REGS_RDX), 304, 512, &token_gva))
return 1;

/*
--
2.53.0.1213.gd9a14994de-goog