Let user-space handle HvGetVpRegisters and HvSetVpRegisters as they are
VTL aware hypercalls used solely in the context of VSM. Additionally,
expose the cpuid bit.

Signed-off-by: Nicolas Saenz Julienne <nsa...@amazon.com>
---
 Documentation/virt/kvm/api.rst    | 10 ++++++++++
 arch/x86/kvm/hyperv.c             | 15 +++++++++++++++
 include/asm-generic/hyperv-tlfs.h |  1 +
 3 files changed, 26 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index e664c54a13b04..05b01b00a395c 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -8931,3 +8931,13 @@ CPUIDs map to KVM functionality.
 This CPUID indicates that KVM supports retuning data to the guest in response
 to a hypercall using the XMM registers. It also extends ``struct
 kvm_hyperv_exit`` to allow passing the XMM data from userspace.
+
+10.2 HV_ACCESS_VP_REGISTERS
+---------------------------
+
+:Location: CPUID.40000003H:EBX[bit 17]
+
+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.
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index d00baf3ffb165..d0edc2bec5a4f 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2425,6 +2425,11 @@ static void kvm_hv_write_xmm(struct kvm_hyperv_xmm_reg 
*xmm)
 
 static bool kvm_hv_is_xmm_output_hcall(u16 code)
 {
+       switch (code) {
+       case HVCALL_GET_VP_REGISTERS:
+               return true;
+       }
+
        return false;
 }
 
@@ -2505,6 +2510,8 @@ static bool is_xmm_fast_hypercall(struct kvm_hv_hcall *hc)
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
        case HVCALL_SEND_IPI_EX:
+       case HVCALL_GET_VP_REGISTERS:
+       case HVCALL_SET_VP_REGISTERS:
                return true;
        }
 
@@ -2543,6 +2550,10 @@ static bool hv_check_hypercall_access(struct kvm_vcpu_hv 
*hv_vcpu, u16 code)
                 */
                return !kvm_hv_is_syndbg_enabled(hv_vcpu->vcpu) ||
                        hv_vcpu->cpuid_cache.features_ebx & HV_DEBUGGING;
+       case HVCALL_GET_VP_REGISTERS:
+       case HVCALL_SET_VP_REGISTERS:
+               return hv_vcpu->cpuid_cache.features_ebx &
+                       HV_ACCESS_VP_REGISTERS;
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
        case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
                if (!(hv_vcpu->cpuid_cache.enlightenments_eax &
@@ -2727,6 +2738,9 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
                        break;
                }
                goto hypercall_userspace_exit;
+       case HVCALL_GET_VP_REGISTERS:
+       case HVCALL_SET_VP_REGISTERS:
+               goto hypercall_userspace_exit;
        default:
                ret = HV_STATUS_INVALID_HYPERCALL_CODE;
                break;
@@ -2898,6 +2912,7 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct 
kvm_cpuid2 *cpuid,
                        ent->ebx |= HV_POST_MESSAGES;
                        ent->ebx |= HV_SIGNAL_EVENTS;
                        ent->ebx |= HV_ENABLE_EXTENDED_HYPERCALLS;
+                       ent->ebx |= HV_ACCESS_VP_REGISTERS;
 
                        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 28cde641b5474..9e909f0834598 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -90,6 +90,7 @@
 #define HV_DEBUGGING                           BIT(11)
 #define HV_CPU_MANAGEMENT                      BIT(12)
 #define HV_ACCESS_VSM                          BIT(16)
+#define HV_ACCESS_VP_REGISTERS                 BIT(17)
 #define HV_ENABLE_EXTENDED_HYPERCALLS          BIT(20)
 #define HV_ISOLATION                           BIT(22)
 
-- 
2.40.1


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