[PATCH RFC v2 15/22] KVM: arm64: Implement SME vector length configuration

From: Mark Brown <broonie@kernel.org>
To: Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	 James Morse <james.morse@arm.com>,
	 Suzuki K Poulose <suzuki.poulose@arm.com>,
	 Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,  Shuah Khan <shuah@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	 linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	 linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
	 Mark Brown <broonie@kernel.org>
Subject: [PATCH RFC v2 15/22] KVM: arm64: Implement SME vector length configuration
Date: Fri, 22 Dec 2023 16:21:23 +0000	[thread overview]
Message-ID: <20231222-kvm-arm64-sme-v2-15-da226cb180bb@kernel.org> (raw)
In-Reply-To: <20231222-kvm-arm64-sme-v2-0-da226cb180bb@kernel.org>

Configuration for SME vector lengths is done using a virtual register as
for SVE, hook up the implementation for the virtual register.  Since we
do not yet have support for any of the new SME registers stub register
access functions are provided.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/uapi/asm/kvm.h |  9 ++++
 arch/arm64/kvm/guest.c            | 94 +++++++++++++++++++++++++++++++--------
 2 files changed, 84 insertions(+), 19 deletions(-)

diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 3048890fac68..02642bb96496 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -353,6 +353,15 @@ struct kvm_arm_counter_offset {
 #define KVM_ARM64_SVE_VLS_WORDS	\
 	((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1)
 
+/* SME registers */
+#define KVM_REG_ARM64_SME		(0x17 << KVM_REG_ARM_COPROC_SHIFT)
+
+/* Vector lengths pseudo-register: */
+#define KVM_REG_ARM64_SME_VLS		(KVM_REG_ARM64 | KVM_REG_ARM64_SME | \
+					 KVM_REG_SIZE_U512 | 0xffff)
+#define KVM_ARM64_SME_VLS_WORDS	\
+	((KVM_ARM64_SVE_VQ_MAX - KVM_ARM64_SVE_VQ_MIN) / 64 + 1)
+
 /* Bitmap feature firmware registers */
 #define KVM_REG_ARM_FW_FEAT_BMAP		(0x0016 << KVM_REG_ARM_COPROC_SHIFT)
 #define KVM_REG_ARM_FW_FEAT_BMAP_REG(r)		(KVM_REG_ARM64 | KVM_REG_SIZE_U64 | \
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 6e116fd8a917..30446ae357f0 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -309,22 +309,20 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 #define vq_mask(vq) ((u64)1 << ((vq) - SVE_VQ_MIN) % 64)
 #define vq_present(vqs, vq) (!!((vqs)[vq_word(vq)] & vq_mask(vq)))
 
-static int get_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+static int get_vec_vls(enum vec_type vec_type, struct kvm_vcpu *vcpu,
+		      const struct kvm_one_reg *reg)
 {
 	unsigned int max_vq, vq;
 	u64 vqs[KVM_ARM64_SVE_VLS_WORDS];
 
-	if (!vcpu_has_sve(vcpu))
-		return -ENOENT;
-
-	if (WARN_ON(!sve_vl_valid(vcpu->arch.max_vl[ARM64_VEC_SVE])))
+	if (WARN_ON(!sve_vl_valid(vcpu->arch.max_vl[vec_type])))
 		return -EINVAL;
 
 	memset(vqs, 0, sizeof(vqs));
 
-	max_vq = vcpu_sve_max_vq(vcpu);
+	max_vq = vcpu_vec_max_vq(vec_type, vcpu);
 	for (vq = SVE_VQ_MIN; vq <= max_vq; ++vq)
-		if (sve_vq_available(vq))
+		if (vq_available(vec_type, vq))
 			vqs[vq_word(vq)] |= vq_mask(vq);
 
 	if (copy_to_user((void __user *)reg->addr, vqs, sizeof(vqs)))
@@ -333,18 +331,13 @@ static int get_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	return 0;
 }
 
-static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+static int set_vec_vls(enum vec_type vec_type, struct kvm_vcpu *vcpu,
+		       const struct kvm_one_reg *reg)
 {
 	unsigned int max_vq, vq;
 	u64 vqs[KVM_ARM64_SVE_VLS_WORDS];
 
-	if (!vcpu_has_sve(vcpu))
-		return -ENOENT;
-
-	if (kvm_arm_vcpu_vec_finalized(vcpu))
-		return -EPERM; /* too late! */
-
-	if (WARN_ON(vcpu->arch.sve_state))
+	if (WARN_ON(!sve_vl_valid(vcpu->arch.max_vl[vec_type])))
 		return -EINVAL;
 
 	if (copy_from_user(vqs, (const void __user *)reg->addr, sizeof(vqs)))
@@ -355,18 +348,18 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 		if (vq_present(vqs, vq))
 			max_vq = vq;
 
-	if (max_vq > sve_vq_from_vl(kvm_vec_max_vl[ARM64_VEC_SVE]))
+	if (max_vq > sve_vq_from_vl(kvm_vec_max_vl[vec_type]))
 		return -EINVAL;
 
 	/*
 	 * Vector lengths supported by the host can't currently be
 	 * hidden from the guest individually: instead we can only set a
-	 * maximum via ZCR_EL2.LEN.  So, make sure the available vector
+	 * maximum via xCR_EL2.LEN.  So, make sure the available vector
 	 * lengths match the set requested exactly up to the requested
 	 * maximum:
 	 */
 	for (vq = SVE_VQ_MIN; vq <= max_vq; ++vq)
-		if (vq_present(vqs, vq) != sve_vq_available(vq))
+		if (vq_present(vqs, vq) != vq_available(vec_type, vq))
 			return -EINVAL;
 
 	/* Can't run with no vector lengths at all: */
@@ -374,11 +367,33 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 		return -EINVAL;
 
 	/* vcpu->arch.sve_state will be alloc'd by kvm_vcpu_finalize_sve() */
-	vcpu->arch.max_vl[ARM64_VEC_SVE] = sve_vl_from_vq(max_vq);
+	vcpu->arch.max_vl[vec_type] = sve_vl_from_vq(max_vq);
 
 	return 0;
 }
 
+static int get_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	if (!vcpu_has_sve(vcpu))
+		return -ENOENT;
+
+	return get_vec_vls(ARM64_VEC_SVE, vcpu, reg);
+}
+
+static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	if (!vcpu_has_sve(vcpu))
+		return -ENOENT;
+
+	if (kvm_arm_vcpu_vec_finalized(vcpu))
+		return -EPERM; /* too late! */
+
+	if (WARN_ON(vcpu->arch.sve_state))
+		return -EINVAL;
+
+	return set_vec_vls(ARM64_VEC_SVE, vcpu, reg);
+}
+
 #define SVE_REG_SLICE_SHIFT	0
 #define SVE_REG_SLICE_BITS	5
 #define SVE_REG_ID_SHIFT	(SVE_REG_SLICE_SHIFT + SVE_REG_SLICE_BITS)
@@ -532,6 +547,45 @@ static int set_sve_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	return 0;
 }
 
+static int get_sme_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	if (!vcpu_has_sme(vcpu))
+		return -ENOENT;
+
+	return get_vec_vls(ARM64_VEC_SME, vcpu, reg);
+}
+
+static int set_sme_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	if (!vcpu_has_sme(vcpu))
+		return -ENOENT;
+
+	if (kvm_arm_vcpu_vec_finalized(vcpu))
+		return -EPERM; /* too late! */
+
+	if (WARN_ON(vcpu->arch.sme_state))
+		return -EINVAL;
+
+	return set_vec_vls(ARM64_VEC_SME, vcpu, reg);
+}
+
+static int get_sme_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	/* Handle the KVM_REG_ARM64_SME_VLS pseudo-reg as a special case: */
+	if (reg->id == KVM_REG_ARM64_SME_VLS)
+		return get_sme_vls(vcpu, reg);
+
+	return -EINVAL;
+}
+
+static int set_sme_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
+	/* Handle the KVM_REG_ARM64_SME_VLS pseudo-reg as a special case: */
+	if (reg->id == KVM_REG_ARM64_SME_VLS)
+		return set_sme_vls(vcpu, reg);
+
+	return -EINVAL;
+}
 int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
 {
 	return -EINVAL;
@@ -771,6 +825,7 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	case KVM_REG_ARM_FW_FEAT_BMAP:
 		return kvm_arm_get_fw_reg(vcpu, reg);
 	case KVM_REG_ARM64_SVE:	return get_sve_reg(vcpu, reg);
+	case KVM_REG_ARM64_SME:	return get_sme_reg(vcpu, reg);
 	}
 
 	if (is_timer_reg(reg->id))
@@ -791,6 +846,7 @@ int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	case KVM_REG_ARM_FW_FEAT_BMAP:
 		return kvm_arm_set_fw_reg(vcpu, reg);
 	case KVM_REG_ARM64_SVE:	return set_sve_reg(vcpu, reg);
+	case KVM_REG_ARM64_SME:	return set_sme_reg(vcpu, reg);
 	}
 
 	if (is_timer_reg(reg->id))

-- 
2.30.2

