On 11/1/2023 12:21 PM, Chao Gao wrote:
On Thu, Sep 14, 2023 at 02:33:24AM -0400, Yang Weijiang wrote:Per SDM description(Vol.3D, Appendix A.1): "If bit 56 is read as 1, software can use VM entry to deliver a hardware exception with or without an error code, regardless of vector" Modify has_error_code check before inject events to nested guest. Only enforce the check when guest is in real mode, the exception is not hard exception and the platform doesn't enumerate bit56 in VMX_BASIC, in all other case ignore the check to make the logic consistent with SDM. Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx> --- arch/x86/kvm/vmx/nested.c | 22 ++++++++++++++-------- arch/x86/kvm/vmx/nested.h | 5 +++++ 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index c5ec0ef51ff7..78a3be394d00 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -1205,9 +1205,9 @@ static int vmx_restore_vmx_basic(struct vcpu_vmx *vmx, u64 data) { const u64 feature_and_reserved = /* feature (except bit 48; see below) */ - BIT_ULL(49) | BIT_ULL(54) | BIT_ULL(55) | + BIT_ULL(49) | BIT_ULL(54) | BIT_ULL(55) | BIT_ULL(56) | /* reserved */ - BIT_ULL(31) | GENMASK_ULL(47, 45) | GENMASK_ULL(63, 56); + BIT_ULL(31) | GENMASK_ULL(47, 45) | GENMASK_ULL(63, 57); u64 vmx_basic = vmcs_config.nested.basic; if (!is_bitwise_subset(vmx_basic, data, feature_and_reserved)) @@ -2846,12 +2846,16 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu, CC(intr_type == INTR_TYPE_OTHER_EVENT && vector != 0)) return -EINVAL; - /* VM-entry interruption-info field: deliver error code */ - should_have_error_code = - intr_type == INTR_TYPE_HARD_EXCEPTION && prot_mode && - x86_exception_has_error_code(vector); - if (CC(has_error_code != should_have_error_code)) - return -EINVAL; + if (!prot_mode || intr_type != INTR_TYPE_HARD_EXCEPTION || + !nested_cpu_has_no_hw_errcode_cc(vcpu)) { + /* VM-entry interruption-info field: deliver error code */ + should_have_error_code = + intr_type == INTR_TYPE_HARD_EXCEPTION && + prot_mode && + x86_exception_has_error_code(vector); + if (CC(has_error_code != should_have_error_code)) + return -EINVAL; + }prot_mode and intr_type are used twice, making the code a little hard to read. how about: /* * Cannot deliver error code in real mode or if the * interruption type is not hardware exception. For other * cases, do the consistency check only if the vCPU doesn't * enumerate VMX_BASIC_NO_HW_ERROR_CODE_CC. */ if (!prot_mode || intr_type != INTR_TYPE_HARD_EXCEPTION) { if (CC(has_error_code)) return -EINVAL; } else if (!nested_cpu_has_no_hw_errcode_cc(vcpu)) { if (CC(has_error_code != x86_exception_has_error_code(vector))) return -EINVAL; } and drop should_have_error_code.
The change looks clearer, I'll take it, thanks!
