Messages in this thread | | | Subject | Re: [PATCH v3 1/3] KVM: SVM: use vmsave/vmload for saving/restoring additional host state | From | Tom Lendacky <> | Date | Thu, 7 Jan 2021 09:32:37 -0600 |
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On 1/5/21 11:20 AM, Sean Christopherson wrote: > 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()?
Yes, it should now. The SEV-ES support added the SME encryption bit to the MSR_VM_HSAVE_PA MSR, so we need to be consistent in how the data is read and written.
Thanks, Tom
> >> } >> >> /* > > ... > >> 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://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.kernel.org%2Fr%2F20201231002702.2223707-8-seanjc%40google.com&data=04%7C01%7Cthomas.lendacky%40amd.com%7C5125acb3a3384ee75a5c08d8b19e2888%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637454640159484993%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Q%2F%2B7kxE9pcV%2BelzHbeRpvs8wlQGQkirKUPg7fBP3QbU%3D&reserved=0 > >> + >> pop %_ASM_BX >> >> #ifdef CONFIG_X86_64 >> -- >> 2.25.1 >>
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