On Tue, Jan 05, 2021, Michael Roth wrote:
> @@ -3703,16 +3688,9 @@ static noinstr void svm_vcpu_enter_exit(struct
> kvm_vcpu *vcpu,
> if (sev_es_guest(svm->vcpu.kvm)) {
> __svm_sev_es_vcpu_run(svm->vmcb_pa);
> } else {
> - __svm_vcpu_run(svm->vmcb_pa, (unsigned long
> *)&svm->vcpu.arch.regs);
> -
> -#ifdef CONFIG_X86_64
> - native_wrmsrl(MSR_GS_BASE, svm->host.gs_base);
> -#else
> - loadsegment(fs, svm->host.fs);
> -#ifndef CONFIG_X86_32_LAZY_GS
> - loadsegment(gs, svm->host.gs);
> -#endif
> -#endif
> + __svm_vcpu_run(svm->vmcb_pa, (unsigned long
> *)&svm->vcpu.arch.regs,
> + page_to_phys(per_cpu(svm_data,
> + vcpu->cpu)->save_area));
Does this need to use __sme_page_pa()?
> }
>
> /*
...
> diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
> index 6feb8c08f45a..89f4e8e7bf0e 100644
> --- a/arch/x86/kvm/svm/vmenter.S
> +++ b/arch/x86/kvm/svm/vmenter.S
> @@ -33,6 +33,7 @@
> * __svm_vcpu_run - Run a vCPU via a transition to SVM guest mode
> * @vmcb_pa: unsigned long
> * @regs: unsigned long * (to guest registers)
> + * @hostsa_pa: unsigned long
> */
> SYM_FUNC_START(__svm_vcpu_run)
> push %_ASM_BP
> @@ -47,6 +48,9 @@ SYM_FUNC_START(__svm_vcpu_run)
> #endif
> push %_ASM_BX
>
> + /* Save @hostsa_pa */
> + push %_ASM_ARG3
> +
> /* Save @regs. */
> push %_ASM_ARG2
>
> @@ -154,6 +158,12 @@ SYM_FUNC_START(__svm_vcpu_run)
> xor %r15d, %r15d
> #endif
>
> + /* "POP" @hostsa_pa to RAX. */
> + pop %_ASM_AX
> +
> + /* Restore host user state and FS/GS base */
> + vmload %_ASM_AX
This VMLOAD needs the "handle fault on reboot" goo. Seeing the code, I think
I'd prefer to handle this in C code, especially if Paolo takes the svm_ops.h
patch[*]. Actually, I think with that patch it'd make sense to move the
existing VMSAVE+VMLOAD for the guest into svm.c, too. And completely unrelated,
the fault handling in svm/vmenter.S can be cleaned up a smidge to eliminate the
JMPs.
Paolo, what do you think about me folding these patches into my series to do the
above cleanups? And maybe sending a pull request for the end result? (I'd also
like to add on a patch to use the user return MSR mechanism for MSR_TSC_AUX).
[*] https://lkml.kernel.org/r/[email protected]
> +
> pop %_ASM_BX
>
> #ifdef CONFIG_X86_64
> --
> 2.25.1
>
