Messages in this thread | | | Date | Tue, 4 May 2021 17:09:49 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH v3 2/2] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall |
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On Sat, May 01, 2021, Paolo Bonzini wrote: > - make it completely independent from migration, i.e. it's just a facet of > MSR_KVM_PAGE_ENC_STATUS saying whether the bitmap is up-to-date. It would > use CPUID bit as the encryption status bitmap and have no code at all in KVM > (userspace needs to set up the filter and implement everything).
If the bit is purely a "page encryption status is up-to-date", what about overloading KVM_HC_PAGE_ENC_STATUS to handle that status update as well? That would eliminate my biggest complaint about having what is effectively a single paravirt feature split into two separate, but intertwined chunks of ABI.
#define KVM_HC_PAGE_ENC_UPDATE 12
#define KVM_HC_PAGE_ENC_REGION_UPDATE 0 /* encrypted vs. plain text */ #define KVM_HC_PAGE_ENC_STATUS_UPDATE 1 /* up-to-date vs. stale */
ret = -KVM_ENOSYS; if (!vcpu->kvm->arch.hypercall_exit_enabled) break;
ret = -EINVAL; if (a0 == KVM_HC_PAGE_ENC_REGION_UPDATE) { u64 gpa = a1, npages = a2;
if (!PAGE_ALIGNED(gpa) || !npages || gpa_to_gfn(gpa) + npages <= gpa_to_gfn(gpa)) break; } else if (a0 != KVM_HC_PAGE_ENC_STATUS_UPDATE) { break; }
vcpu->run->exit_reason = KVM_EXIT_HYPERCALL; vcpu->run->hypercall.nr = KVM_HC_PAGE_ENC_STATUS; vcpu->run->hypercall.args[0] = a0; vcpu->run->hypercall.args[1] = a1; vcpu->run->hypercall.args[2] = a2; vcpu->run->hypercall.args[3] = a3; vcpu->run->hypercall.longmode = op_64_bit; vcpu->arch.complete_userspace_io = complete_hypercall_exit; return 0;
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