linux-kernel - [PATCH RFC v2 07/22] KVM: arm64: Define guest flags for SME

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Message-Id: <20231222-kvm-arm64-sme-v2-7-da226cb180bb@kernel.org>
Date: Fri, 22 Dec 2023 16:21:15 +0000
From: Mark Brown <broonie@...nel.org>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
 James Morse <james.morse@....com>, 
 Suzuki K Poulose <suzuki.poulose@....com>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Paolo Bonzini <pbonzini@...hat.com>, Jonathan Corbet <corbet@....net>, 
 Shuah Khan <shuah@...nel.org>
Cc: 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 RFC v2 07/22] KVM: arm64: Define guest flags for SME

Introduce flags for the individually selectable features in SME which
add architectural state:

 - Base SME which adds the system registers and ZA matrix.
 - SME 2 which adds ZT0.
 - FA64 which enables access to the full floating point feature set in
   streaming mode, including adding FFR in streaming mode.

along with helper functions for checking them.

These will be used by further patches actually implementing support for
SME in guests.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 arch/arm64/include/asm/kvm_host.h          | 13 +++++++++++++
 arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 10 ++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3b557ffb8e7b..461068c99b61 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -710,6 +710,12 @@ struct kvm_vcpu_arch {
 #define GUEST_HAS_PTRAUTH	__vcpu_single_flag(cflags, BIT(2))
 /* KVM_ARM_VCPU_INIT completed */
 #define VCPU_INITIALIZED	__vcpu_single_flag(cflags, BIT(3))
+/* SME1 exposed to guest */
+#define GUEST_HAS_SME		__vcpu_single_flag(cflags, BIT(4))
+/* SME2 exposed to guest */
+#define GUEST_HAS_SME2		__vcpu_single_flag(cflags, BIT(5))
+/* FA64 exposed to guest */
+#define GUEST_HAS_FA64		__vcpu_single_flag(cflags, BIT(6))
 
 /* Exception pending */
 #define PENDING_EXCEPTION	__vcpu_single_flag(iflags, BIT(0))
@@ -780,6 +786,13 @@ struct kvm_vcpu_arch {
 #define vcpu_has_sve(vcpu) (system_supports_sve() &&			\
 			    vcpu_get_flag(vcpu, GUEST_HAS_SVE))
 
+#define vcpu_has_sme(vcpu) (system_supports_sme() &&			\
+			    vcpu_get_flag(vcpu, GUEST_HAS_SME))
+#define vcpu_has_sme2(vcpu) (system_supports_sme2() &&			\
+			     vcpu_get_flag(vcpu, GUEST_HAS_SME2))
+#define vcpu_has_fa64(vcpu) (system_supports_fa64() &&			\
+			     vcpu_get_flag(vcpu, GUEST_HAS_FA64))
+
 #ifdef CONFIG_ARM64_PTR_AUTH
 #define vcpu_has_ptrauth(vcpu)						\
 	((cpus_have_final_cap(ARM64_HAS_ADDRESS_AUTH) ||		\
diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
index bb6b571ec627..fb84834cd2a0 100644
--- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
+++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
@@ -21,6 +21,16 @@ static inline void __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
 	ctxt_sys_reg(ctxt, MDSCR_EL1)	= read_sysreg(mdscr_el1);
 }
 
+static inline bool ctxt_has_sme(struct kvm_cpu_context *ctxt)
+{
+	struct kvm_vcpu *vcpu = ctxt->__hyp_running_vcpu;
+
+	if (!vcpu)
+		vcpu = container_of(ctxt, struct kvm_vcpu, arch.ctxt);
+
+	return vcpu_has_sme(vcpu);
+}
+
 static inline void __sysreg_save_user_state(struct kvm_cpu_context *ctxt)
 {
 	ctxt_sys_reg(ctxt, TPIDR_EL0)	= read_sysreg(tpidr_el0);

-- 
2.30.2