Re: [RFC 11/33] KVM: x86: hyper-v: Handle GET/SET_VP_REGISTER hcall in user-space

[Alexander Graf]

On 08.11.23 12:17, Nicolas Saenz Julienne wrote:

Let user-space handle HVCALL_GET_VP_REGISTERS and
HVCALL_SET_VP_REGISTERS through the KVM_EXIT_HYPERV_HVCALL exit reason.
Additionally, expose the cpuid bit.

Signed-off-by: Nicolas Saenz Julienne 
---
  arch/x86/kvm/hyperv.c | 9 +
  include/asm-generic/hyperv-tlfs.h | 1 +
  2 files changed, 10 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index caaa859932c5..a3970d52eef1 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2456,6 +2456,9 @@ static void kvm_hv_write_xmm(struct kvm_hyperv_xmm_reg 
*xmm)
  
  static bool kvm_hv_is_xmm_output_hcall(u16 code)

  {
+   if (code == HVCALL_GET_VP_REGISTERS)
+   return true;
+
return false;
  }
  
@@ -2520,6 +2523,8 @@ 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;
}
  
@@ -2738,6 +2743,9 @@ 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;
@@ -2903,6 +2911,7 @@ 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;



Do we need to guard this?


Alex




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[RFC 11/33] KVM: x86: hyper-v: Handle GET/SET_VP_REGISTER hcall in user-space

[Nicolas Saenz Julienne]

Let user-space handle HVCALL_GET_VP_REGISTERS and
HVCALL_SET_VP_REGISTERS through the KVM_EXIT_HYPERV_HVCALL exit reason.
Additionally, expose the cpuid bit.

Signed-off-by: Nicolas Saenz Julienne 
---
 arch/x86/kvm/hyperv.c | 9 +
 include/asm-generic/hyperv-tlfs.h | 1 +
 2 files changed, 10 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index caaa859932c5..a3970d52eef1 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2456,6 +2456,9 @@ static void kvm_hv_write_xmm(struct kvm_hyperv_xmm_reg 
*xmm)
 
 static bool kvm_hv_is_xmm_output_hcall(u16 code)
 {
+   if (code == HVCALL_GET_VP_REGISTERS)
+   return true;
+
return false;
 }
 
@@ -2520,6 +2523,8 @@ 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;
}
 
@@ -2738,6 +2743,9 @@ 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;
@@ -2903,6 +2911,7 @@ 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 40d7dc793c03..24ea699a3d8e 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -89,6 +89,7 @@
 #define HV_ACCESS_STATSBIT(8)
 #define HV_DEBUGGING   BIT(11)
 #define HV_CPU_MANAGEMENT  BIT(12)
+#define HV_ACCESS_VP_REGISTERS BIT(17)
 #define HV_ENABLE_EXTENDED_HYPERCALLS  BIT(20)
 #define HV_ISOLATION   BIT(22)
 
-- 
2.40.1