Messages in this thread Patch in this message | | | Subject | Re: [PATCH v10 08/16] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall | From | Tom Lendacky <> | Date | Thu, 4 Feb 2021 10:03:14 -0600 |
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On 2/3/21 6:38 PM, Ashish Kalra wrote: > From: Brijesh Singh <brijesh.singh@amd.com> > > This hypercall is used by the SEV guest to notify a change in the page > encryption status to the hypervisor. The hypercall should be invoked > only when the encryption attribute is changed from encrypted -> decrypted > and vice versa. By default all guest pages are considered encrypted. > > The patch introduces a new shared pages list implemented as a > sorted linked list to track the shared/unencrypted regions marked by the > guest hypercall. >
...
> + > + if (enc) { > + ret = remove_shared_region(gfn_start, gfn_end, > + &sev->shared_pages_list); > + if (ret != -ENOMEM) > + sev->shared_pages_list_count += ret; > + } else { > + ret = add_shared_region(gfn_start, gfn_end, > + &sev->shared_pages_list); > + if (ret > 0) > + sev->shared_pages_list_count++; > + }
I would move the shared_pages_list_count updates into the add/remove functions and then just return 0 or a -EXXXX error code from those functions. It seems simpler than "adding" ret or checking for a greater than 0 return code.
Thanks, Tom
> + > + mutex_unlock(&kvm->lock); > + return ret; > +} > + > int svm_mem_enc_op(struct kvm *kvm, void __user *argp) > { > struct kvm_sev_cmd sev_cmd; > @@ -1693,6 +1842,7 @@ void sev_vm_destroy(struct kvm *kvm) > > sev_unbind_asid(kvm, sev->handle); > sev_asid_free(sev->asid); > + sev->shared_pages_list_count = 0; > } > > void __init sev_hardware_setup(void) > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index f923e14e87df..bb249ec625fc 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -4536,6 +4536,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { > .complete_emulated_msr = svm_complete_emulated_msr, > > .vcpu_deliver_sipi_vector = svm_vcpu_deliver_sipi_vector, > + > + .page_enc_status_hc = svm_page_enc_status_hc, > }; > > static struct kvm_x86_init_ops svm_init_ops __initdata = { > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index 0fe874ae5498..6437c1fa1f24 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -79,6 +79,9 @@ struct kvm_sev_info { > unsigned long pages_locked; /* Number of pages locked */ > struct list_head regions_list; /* List of registered regions */ > u64 ap_jump_table; /* SEV-ES AP Jump Table address */ > + /* List and count of shared pages */ > + int shared_pages_list_count; > + struct list_head shared_pages_list; > }; > > struct kvm_svm { > @@ -472,6 +475,8 @@ int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr, > bool has_error_code, u32 error_code); > int nested_svm_exit_special(struct vcpu_svm *svm); > void sync_nested_vmcb_control(struct vcpu_svm *svm); > +int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa, > + unsigned long npages, unsigned long enc); > > extern struct kvm_x86_nested_ops svm_nested_ops; > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index cc60b1fc3ee7..bcbf53851612 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -7705,6 +7705,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = { > .can_emulate_instruction = vmx_can_emulate_instruction, > .apic_init_signal_blocked = vmx_apic_init_signal_blocked, > .migrate_timers = vmx_migrate_timers, > + .page_enc_status_hc = NULL, > > .msr_filter_changed = vmx_msr_filter_changed, > .complete_emulated_msr = kvm_complete_insn_gp, > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 76bce832cade..2f17f0f9ace7 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -8162,6 +8162,12 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > kvm_sched_yield(vcpu->kvm, a0); > ret = 0; > break; > + case KVM_HC_PAGE_ENC_STATUS: > + ret = -KVM_ENOSYS; > + if (kvm_x86_ops.page_enc_status_hc) > + ret = kvm_x86_ops.page_enc_status_hc(vcpu->kvm, > + a0, a1, a2); > + break; > default: > ret = -KVM_ENOSYS; > break; > diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h > index 8b86609849b9..847b83b75dc8 100644 > --- a/include/uapi/linux/kvm_para.h > +++ b/include/uapi/linux/kvm_para.h > @@ -29,6 +29,7 @@ > #define KVM_HC_CLOCK_PAIRING 9 > #define KVM_HC_SEND_IPI 10 > #define KVM_HC_SCHED_YIELD 11 > +#define KVM_HC_PAGE_ENC_STATUS 12 > > /* > * hypercalls use architecture specific >
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