linux-kernel - [RFC 11/33] KVM: x86: hyper-v: Handle GET/SET_VP

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Message-ID: <20231108111806.92604-12-nsaenz@amazon.com>
Date:   Wed, 8 Nov 2023 11:17:44 +0000
From:   Nicolas Saenz Julienne <nsaenz@...zon.com>
To:     <kvm@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-hyperv@...r.kernel.org>,
        <pbonzini@...hat.com>, <seanjc@...gle.com>, <vkuznets@...hat.com>,
        <anelkz@...zon.com>, <graf@...zon.com>, <dwmw@...zon.co.uk>,
        <jgowans@...zon.com>, <corbert@....net>, <kys@...rosoft.com>,
        <haiyangz@...rosoft.com>, <decui@...rosoft.com>, <x86@...nel.org>,
        <linux-doc@...r.kernel.org>,
        Nicolas Saenz Julienne <nsaenz@...zon.com>
Subject: [RFC 11/33] KVM: x86: hyper-v: Handle GET/SET_VP_REGISTER hcall in user-space

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 <nsaenz@...zon.com>
---
 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_STATS				BIT(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