[RFC PATCH v1 12/26] KVM: arm64: Allow userspace to receive SHARE and UNSHARE notifications

From: Fuad Tabba <tabba@google.com>
To: kvm@vger.kernel.org, kvmarm@lists.linux.dev
Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au,
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	 tabba@google.com
Subject: [RFC PATCH v1 12/26] KVM: arm64: Allow userspace to receive SHARE and UNSHARE notifications
Date: Thu, 22 Feb 2024 16:10:33 +0000	[thread overview]
Message-ID: <20240222161047.402609-13-tabba@google.com> (raw)
In-Reply-To: <20240222161047.402609-1-tabba@google.com>

From: Will Deacon <will@kernel.org>

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/kvm/arm.c        | 3 ++-
 arch/arm64/kvm/hypercalls.c | 8 +++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index cd6c4df27c7b..6bba6f1fee88 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -61,7 +61,8 @@ static DEFINE_PER_CPU(unsigned char, kvm_hyp_initialized);
 DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
 /* KVM "vendor" hypercalls which may be forwarded to userspace on request. */
-#define KVM_EXIT_HYPERCALL_VALID_MASK	(0)
+#define KVM_EXIT_HYPERCALL_VALID_MASK	(BIT(ARM_SMCCC_KVM_FUNC_MEM_SHARE) |	\
+					 BIT(ARM_SMCCC_KVM_FUNC_MEM_UNSHARE))
 
 bool is_kvm_arm_initialised(void)
 {
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5e04be7c026a..b93546dd222f 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -83,6 +83,8 @@ static bool kvm_smccc_default_allowed(u32 func_id)
 	 */
 	case ARM_SMCCC_VERSION_FUNC_ID:
 	case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
+	case ARM_SMCCC_VENDOR_HYP_KVM_MEM_SHARE_FUNC_ID:
+	case ARM_SMCCC_VENDOR_HYP_KVM_MEM_UNSHARE_FUNC_ID:
 		return true;
 	default:
 		/* PSCI 0.2 and up is in the 0:0x1f range */
@@ -132,7 +134,7 @@ static bool kvm_smccc_test_fw_bmap(struct kvm_vcpu *vcpu, u32 func_id)
 	}
 }
 
-static int __maybe_unused kvm_vcpu_exit_hcall(struct kvm_vcpu *vcpu, u32 nr, u32 nr_args)
+static int kvm_vcpu_exit_hcall(struct kvm_vcpu *vcpu, u32 nr, u32 nr_args)
 {
 	u64 mask = vcpu->kvm->arch.hypercall_exit_enabled;
 	u32 i;
@@ -398,6 +400,10 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu)
 		pkvm_host_reclaim_page(vcpu->kvm, smccc_get_arg1(vcpu));
 		val[0] = SMCCC_RET_SUCCESS;
 		break;
+	case ARM_SMCCC_VENDOR_HYP_KVM_MEM_SHARE_FUNC_ID:
+		return kvm_vcpu_exit_hcall(vcpu, ARM_SMCCC_KVM_FUNC_MEM_SHARE, 3);
+	case ARM_SMCCC_VENDOR_HYP_KVM_MEM_UNSHARE_FUNC_ID:
+		return kvm_vcpu_exit_hcall(vcpu, ARM_SMCCC_KVM_FUNC_MEM_UNSHARE, 3);
 	case ARM_SMCCC_TRNG_VERSION:
 	case ARM_SMCCC_TRNG_FEATURES:
 	case ARM_SMCCC_TRNG_GET_UUID:
-- 
2.44.0.rc1.240.g4c46232300-goog

