Date:   Tue,  4 Jan 2022 19:49:12 +0000
In-Reply-To: <20220104194918.373612-1-rananta@google.com>
Message-Id: <20220104194918.373612-6-rananta@google.com>
Mime-Version: 1.0
References: <20220104194918.373612-1-rananta@google.com>
Subject: [RFC PATCH v3 05/11] KVM: arm64: Add standard hypervisor firmware register
From:   Raghavendra Rao Ananta <rananta@google.com>
To:     Marc Zyngier <maz@kernel.org>, Andrew Jones <drjones@redhat.com>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Peter Shier <pshier@google.com>,
        Ricardo Koller <ricarkol@google.com>,
        Oliver Upton <oupton@google.com>,
        Reiji Watanabe <reijiw@google.com>,
        Jing Zhang <jingzhangos@google.com>,
        Raghavendra Rao Anata <rananta@google.com>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Introduce the firmware register to hold the standard hypervisor
service calls (owner value 5) as a bitmap. The bitmap represents
the features that'll be enabled for the guest, as configured by
the user-space. Currently, this includes support only for
Paravirtualized time, represented by bit-0.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
---
 arch/arm64/include/asm/kvm_host.h |  2 ++
 arch/arm64/include/uapi/asm/kvm.h |  4 ++++
 arch/arm64/kvm/hypercalls.c       | 17 ++++++++++++++++-
 arch/arm64/kvm/pvtime.c           |  3 +++
 include/kvm/arm_hypercalls.h      |  3 +++
 5 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a32cded0371b..1daf2c0b3b85 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -106,9 +106,11 @@ struct kvm_arch_memory_slot {
  * struct kvm_hvc_desc: KVM ARM64 hypercall descriptor
  *
  * @hvc_std_bmap: Bitmap of standard secure service calls
+ * @hvc_std_hyp_bmap: Bitmap of standard hypervisor service calls
  */
 struct kvm_hvc_desc {
 	u64 hvc_std_bmap;
+	u64 hvc_std_hyp_bmap;
 };
 
 struct kvm_arch {
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 0d6f29c58456..af59c434ae33 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -285,6 +285,10 @@ struct kvm_arm_copy_mte_tags {
 #define KVM_REG_ARM_STD_BIT_TRNG_V1_0		BIT(0)
 #define KVM_REG_ARM_STD_BMAP_BIT_MAX		0       /* Last valid bit */
 
+#define KVM_REG_ARM_STD_HYP_BMAP		KVM_REG_ARM_FW_REG(4)
+#define KVM_REG_ARM_STD_HYP_BIT_PV_TIME		BIT(0)
+#define KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX	0       /* Last valid bit */
+
 /* SVE registers */
 #define KVM_REG_ARM64_SVE		(0x15 << KVM_REG_ARM_COPROC_SHIFT)
 
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 06243e4670eb..9df0221834a3 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -75,6 +75,10 @@ bool kvm_hvc_call_supported(struct kvm_vcpu *vcpu, u32 func_id)
 	case ARM_SMCCC_TRNG_RND64:
 		return kvm_arm_fw_reg_feat_enabled(hvc_desc->hvc_std_bmap,
 						KVM_REG_ARM_STD_BIT_TRNG_V1_0);
+	case ARM_SMCCC_HV_PV_TIME_FEATURES:
+	case ARM_SMCCC_HV_PV_TIME_ST:
+		return kvm_arm_fw_reg_feat_enabled(hvc_desc->hvc_std_hyp_bmap,
+					KVM_REG_ARM_STD_HYP_BIT_PV_TIME);
 	default:
 		/* By default, allow the services that aren't listed here */
 		return true;
@@ -134,7 +138,8 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
 			}
 			break;
 		case ARM_SMCCC_HV_PV_TIME_FEATURES:
-			val[0] = SMCCC_RET_SUCCESS;
+			if (kvm_hvc_call_supported(vcpu, feature))
+				val[0] = SMCCC_RET_SUCCESS;
 			break;
 		}
 		break;
@@ -182,6 +187,7 @@ static const u64 kvm_arm_fw_reg_ids[] = {
 
 static const u64 kvm_arm_fw_reg_bmap_ids[] = {
 	KVM_REG_ARM_STD_BMAP,
+	KVM_REG_ARM_STD_HYP_BMAP,
 };
 
 void kvm_arm_init_hypercalls(struct kvm *kvm)
@@ -189,6 +195,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm)
 	struct kvm_hvc_desc *hvc_desc = &kvm->arch.hvc_desc;
 
 	hvc_desc->hvc_std_bmap = ARM_SMCCC_STD_FEATURES;
+	hvc_desc->hvc_std_hyp_bmap = ARM_SMCCC_STD_HYP_FEATURES;
 }
 
 int kvm_arm_num_fw_bmap_regs(void)
@@ -286,6 +293,9 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	case KVM_REG_ARM_STD_BMAP:
 		kvm_arm_get_fw_reg_bmap(vcpu, hvc_desc->hvc_std_bmap, &val);
 		break;
+	case KVM_REG_ARM_STD_HYP_BMAP:
+		kvm_arm_get_fw_reg_bmap(vcpu, hvc_desc->hvc_std_hyp_bmap, &val);
+		break;
 	default:
 		return -ENOENT;
 	}
@@ -308,6 +318,10 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
 		fw_reg_bmap = &hvc_desc->hvc_std_bmap;
 		fw_reg_features = ARM_SMCCC_STD_FEATURES;
 		break;
+	case KVM_REG_ARM_STD_HYP_BMAP:
+		fw_reg_bmap = &hvc_desc->hvc_std_hyp_bmap;
+		fw_reg_features = ARM_SMCCC_STD_HYP_FEATURES;
+		break;
 	default:
 		return -ENOENT;
 	}
@@ -410,6 +424,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 
 		return 0;
 	case KVM_REG_ARM_STD_BMAP:
+	case KVM_REG_ARM_STD_HYP_BMAP:
 		return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
 	default:
 		return -ENOENT;
diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c
index 78a09f7a6637..4fa436dbd0b7 100644
--- a/arch/arm64/kvm/pvtime.c
+++ b/arch/arm64/kvm/pvtime.c
@@ -37,6 +37,9 @@ long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu)
 	u32 feature = smccc_get_arg1(vcpu);
 	long val = SMCCC_RET_NOT_SUPPORTED;
 
+	if (!kvm_hvc_call_supported(vcpu, feature))
+		return val;
+
 	switch (feature) {
 	case ARM_SMCCC_HV_PV_TIME_FEATURES:
 	case ARM_SMCCC_HV_PV_TIME_ST:
diff --git a/include/kvm/arm_hypercalls.h b/include/kvm/arm_hypercalls.h
index 8fe68d8d6d96..1a79b5f89a24 100644
--- a/include/kvm/arm_hypercalls.h
+++ b/include/kvm/arm_hypercalls.h
@@ -9,6 +9,9 @@
 #define ARM_SMCCC_STD_FEATURES \
 	GENMASK_ULL(KVM_REG_ARM_STD_BMAP_BIT_MAX, 0)
 
+#define ARM_SMCCC_STD_HYP_FEATURES \
+	GENMASK_ULL(KVM_REG_ARM_STD_HYP_BMAP_BIT_MAX, 0)
+
 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu);
 
 static inline u32 smccc_get_function(struct kvm_vcpu *vcpu)
-- 
2.34.1.448.ga2b2bfdf31-goog