Re: [PATCH 07/11] KVM: x86: Add mode-aware versions of kvm__{read,write}() helpers

Huang, Kai
2026-04-14T08:26:50Z

> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -757,7 +757,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm)
>
> svm->vcpu.arch.cr2 = save->cr2;
>
> - kvm_rax_write(vcpu, save->rax);
> + kvm_rax_write_raw(vcpu, save->rax);
> kvm_rsp_write(vcpu, save->rsp);
> kvm_rip_write(vcpu, save->rip);
>
> @@ -1238,7 +1238,7 @@ static int nested_svm_vmexit_update_vmcb12(struct kvm_vcpu *vcpu)
> vmcb12->save.rflags = kvm_get_rflags(vcpu);
> vmcb12->save.rip = kvm_rip_read(vcpu);
> vmcb12->save.rsp = kvm_rsp_read(vcpu);
> - vmcb12->save.rax = kvm_rax_read(vcpu);
> + vmcb12->save.rax = kvm_rax_read_raw(vcpu);

Not sure whether it matters, I think there's an inconsistency here:

The "rax" one has "raw" postfix, but "rsp" doesn't, despite in practice it
is also a "raw" operation. Ditto for "rip", although it will be moved out
of the "regs[]" GPR array.

But maybe they are different?

[...]

> case EXIT_REASON_MSR_WRITE:
> - kvm_rcx_write(vcpu, tdx->vp_enter_args.r12);
> - kvm_rax_write(vcpu, tdx->vp_enter_args.r13 & -1u);
> - kvm_rdx_write(vcpu, tdx->vp_enter_args.r13 >> 32);
> + kvm_ecx_write(vcpu, tdx->vp_enter_args.r12);
> + kvm_eax_write(vcpu, tdx->vp_enter_args.r13 & -1u);

Nit: the "& -1u" isn't needed anymore with using kvm_eax_write(), but maybe
we should just focus on replacing the functions in this patch but leave
cleanup in the future.

[...]

> @@ -12184,23 +12185,23 @@ static void __set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
> vcpu->arch.emulate_regs_need_sync_from_vcpu = true;
> vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
>
> - kvm_rax_write(vcpu, regs->rax);
> - kvm_rbx_write(vcpu, regs->rbx);
> - kvm_rcx_write(vcpu, regs->rcx);
> - kvm_rdx_write(vcpu, regs->rdx);
> - kvm_rsi_write(vcpu, regs->rsi);
> - kvm_rdi_write(vcpu, regs->rdi);
> + kvm_rax_write_raw(vcpu, regs->rax);
> + kvm_rbx_write_raw(vcpu, regs->rbx);
> + kvm_rcx_write_raw(vcpu, regs->rcx);
> + kvm_rdx_write_raw(vcpu, regs->rdx);
> + kvm_rsi_write_raw(vcpu, regs->rsi);
> + kvm_rdi_write_raw(vcpu, regs->rdi);
> kvm_rsp_write(vcpu, regs->rsp);
> - kvm_rbp_write(vcpu, regs->rbp);
> + kvm_rbp_write_raw(vcpu, regs->rbp);
>

Ditto, the "rsp" one stands out. :-)

[...]

> +static __always_inline void kvm_e##lname##_write(struct kvm_vcpu *vcpu, u32 val) \

It seems tab is used before the 'u32 val'. Seems no need.