[PATCH 08/18] KVM: x86: hyper-v: Exit on StartVirtualProcessor and GetVpIndexFromApicId hcalls
From: Nicolas Saenz Julienne <hidden>
Date: 2024-06-09 15:55:27
Also in:
kvm, linux-arch, linux-doc, linux-hyperv, lkml
Subsystem:
documentation, generic include/asm header files, kernel virtual machine (kvm), kernel virtual machine for x86 (kvm/x86), kvm x86 hyper-v (kvm/hyper-v), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Jonathan Corbet, Arnd Bergmann, Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Both HvCallStartVirtualProcessor and GetVpIndexFromApicId are used as part of the Hyper-V VSM CPU bootstrap process, and requires VTL awareness, as such handle the hypercall in user-space. Also, expose the ad-hoc CPUID bit. Note that these hypercalls aren't necessary on Hyper-V guests that don't enable VSM. Signed-off-by: Nicolas Saenz Julienne <redacted> --- Documentation/virt/kvm/api.rst | 11 +++++++++++ arch/x86/kvm/hyperv.c | 7 +++++++ include/asm-generic/hyperv-tlfs.h | 1 + 3 files changed, 19 insertions(+)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 05b01b00a395c..161a772c23c6a 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst@@ -8941,3 +8941,14 @@ This CPUID indicates that KVM supports HvGetVpRegisters and HvSetVpRegisters. Currently, it is only used in conjunction with HV_ACCESS_VSM, and immediately exits to userspace with KVM_EXIT_HYPERV_HCALL as the reason. Userspace is expected to complete the hypercall before resuming execution. + +10.3 HV_START_VIRTUAL_PROCESSOR +------------------------------- + +:Location: CPUID.40000003H:EBX[bit 21] + +This CPUID indicates that KVM supports HvCallStartVirtualProcessor and +HvCallGetVpIndexFromApicId. Currently, it is only used in conjunction with +HV_ACCESS_VSM, and immediately exits to userspace with KVM_EXIT_HYPERV_HCALL as +the reason. Userspace is expected to complete the hypercall before resuming +execution.
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index cbe2aca52514b..dd64f41dc835d 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c@@ -2556,6 +2556,10 @@ static bool hv_check_hypercall_access(struct kvm_vcpu_hv *hv_vcpu, u16 code) case HVCALL_SET_VP_REGISTERS: return hv_vcpu->cpuid_cache.features_ebx & HV_ACCESS_VP_REGISTERS; + case HVCALL_START_VP: + case HVCALL_GET_VP_ID_FROM_APIC_ID: + return hv_vcpu->cpuid_cache.features_ebx & + HV_START_VIRTUAL_PROCESSOR; case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX: case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX: if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
@@ -2743,6 +2747,8 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) case HVCALL_GET_VP_REGISTERS: case HVCALL_SET_VP_REGISTERS: case HVCALL_TRANSLATE_VIRTUAL_ADDRESS: + case HVCALL_START_VP: + case HVCALL_GET_VP_ID_FROM_APIC_ID: goto hypercall_userspace_exit; default: ret = HV_STATUS_INVALID_HYPERCALL_CODE;
@@ -2916,6 +2922,7 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, ent->ebx |= HV_SIGNAL_EVENTS; ent->ebx |= HV_ENABLE_EXTENDED_HYPERCALLS; ent->ebx |= HV_ACCESS_VP_REGISTERS; + ent->ebx |= HV_START_VIRTUAL_PROCESSOR; ent->edx |= HV_X64_HYPERCALL_XMM_INPUT_AVAILABLE; ent->edx |= HV_X64_HYPERCALL_XMM_OUTPUT_AVAILABLE;
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 57c791c555861..e24b88ec4ec00 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h@@ -92,6 +92,7 @@ #define HV_ACCESS_VSM BIT(16) #define HV_ACCESS_VP_REGISTERS BIT(17) #define HV_ENABLE_EXTENDED_HYPERCALLS BIT(20) +#define HV_START_VIRTUAL_PROCESSOR BIT(21) #define HV_ISOLATION BIT(22) /*
--
2.40.1