linux-kernel - [PATCH v5 11/28] KVM: arm64: Define internal features for SME

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250417-kvm-arm64-sme-v5-11-f469a2d5f574@kernel.org>
Date: Thu, 17 Apr 2025 01:25:15 +0100
From: Mark Brown <broonie@...nel.org>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
 Joey Gouly <joey.gouly@....com>, Catalin Marinas <catalin.marinas@....com>, 
 Suzuki K Poulose <suzuki.poulose@....com>, Will Deacon <will@...nel.org>, 
 Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>, 
 Shuah Khan <shuah@...nel.org>
Cc: Dave Martin <Dave.Martin@....com>, Fuad Tabba <tabba@...gle.com>, 
 Mark Rutland <mark.rutland@....com>, linux-arm-kernel@...ts.infradead.org, 
 kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org, kvm@...r.kernel.org, 
 linux-doc@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 Mark Brown <broonie@...nel.org>
Subject: [PATCH v5 11/28] KVM: arm64: Define internal features for SME

In order to simplify interdependencies in the rest of the series define
the feature detection for SME and it's subfeatures.  Due to the need for
vector length configuration we define a flag for SME like for SVE.  We
also have two subfeatures which add architectural state, FA64 and SME2,
which are configured via the normal ID register scheme.

Also provide helpers which check if the vCPU is in streaming mode or has
ZA enabled.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 arch/arm64/include/asm/kvm_host.h | 37 +++++++++++++++++++++++++++++++++++--
 arch/arm64/kvm/sys_regs.c         |  2 +-
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e828607653c7..a6690893ec5e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -39,7 +39,7 @@
 
 #define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS
 
-#define KVM_VCPU_MAX_FEATURES 7
+#define KVM_VCPU_MAX_FEATURES 9
 #define KVM_VCPU_VALID_FEATURES	(BIT(KVM_VCPU_MAX_FEATURES) - 1)
 
 #define KVM_REQ_SLEEP \
@@ -348,6 +348,8 @@ struct kvm_arch {
 #define KVM_ARCH_FLAG_GUEST_HAS_SVE			9
 	/* MIDR_EL1, REVIDR_EL1, and AIDR_EL1 are writable from userspace */
 #define KVM_ARCH_FLAG_WRITABLE_IMP_ID_REGS		10
+	/* SME exposed to guest */
+#define KVM_ARCH_FLAG_GUEST_HAS_SME			11
 	unsigned long flags;
 
 	/* VM-wide vCPU feature set */
@@ -982,7 +984,16 @@ struct kvm_vcpu_arch {
 #define vcpu_has_sve(vcpu)	kvm_has_sve((vcpu)->kvm)
 #endif
 
-#define vcpu_has_vec(vcpu) vcpu_has_sve(vcpu)
+#define kvm_has_sme(kvm)	(system_supports_sme() &&		\
+				 test_bit(KVM_ARCH_FLAG_GUEST_HAS_SME, &(kvm)->arch.flags))
+
+#ifdef __KVM_NVHE_HYPERVISOR__
+#define vcpu_has_sme(vcpu)	kvm_has_sme(kern_hyp_va((vcpu)->kvm))
+#else
+#define vcpu_has_sme(vcpu)	kvm_has_sme((vcpu)->kvm)
+#endif
+
+#define vcpu_has_vec(vcpu) (vcpu_has_sve(vcpu) || vcpu_has_sme(vcpu))
 
 #ifdef CONFIG_ARM64_PTR_AUTH
 #define vcpu_has_ptrauth(vcpu)						\
@@ -1596,4 +1607,26 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
 #define kvm_has_s1poe(k)				\
 	(kvm_has_feat((k), ID_AA64MMFR3_EL1, S1POE, IMP))
 
+#define kvm_has_fa64(k)					\
+	(system_supports_fa64() &&			\
+	 kvm_has_feat((k), ID_AA64SMFR0_EL1, FA64, IMP))
+
+#define kvm_has_sme2(k)					\
+	(system_supports_sme2() &&			\
+	 kvm_has_feat((k), ID_AA64PFR1_EL1, SME, SME2))
+
+#ifdef __KVM_NVHE_HYPERVISOR__
+#define vcpu_has_sme2(vcpu)	kvm_has_sme2(kern_hyp_va((vcpu)->kvm))
+#define vcpu_has_fa64(vcpu)	kvm_has_fa64(kern_hyp_va((vcpu)->kvm))
+#else
+#define vcpu_has_sme2(vcpu)	kvm_has_sme2((vcpu)->kvm)
+#define vcpu_has_fa64(vcpu)	kvm_has_fa64((vcpu)->kvm)
+#endif
+
+#define vcpu_in_streaming_mode(vcpu) \
+	(__vcpu_sys_reg(vcpu, SVCR) & SVCR_SM_MASK)
+
+#define vcpu_za_enabled(vcpu) \
+	(__vcpu_sys_reg(vcpu, SVCR) & SVCR_ZA_MASK)
+
 #endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 005ad28f7306..0fc33134ac41 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1772,7 +1772,7 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
 static unsigned int sme_visibility(const struct kvm_vcpu *vcpu,
 				   const struct sys_reg_desc *rd)
 {
-	if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, SME, IMP))
+	if (vcpu_has_sme(vcpu))
 		return 0;
 
 	return REG_HIDDEN;

-- 
2.39.5