[PATCH RFC v3 16/27] KVM: arm64: Add definitions for SME control register

[Mark Brown <broonie@kernel.org>]

SME is configured by the system registers SMCR_EL1 and SMCR_EL2, add
definitions and userspace access for them.  They will be context
switched together with the rest of SME state.

In systems with SME priority support there are additional registers
SMPRI_EL1 and SMPRIMAP_EL2 managing the priorities however we do not
currently have any support for SME priorities and mask that support out
from guests.  The intention is to revist this once we have physical
implementations and can properly evaluate the practical impacts that
they have.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/kvm_host.h     |  6 ++++++
 arch/arm64/include/asm/vncr_mapping.h |  1 +
 arch/arm64/kvm/sys_regs.c             | 37 ++++++++++++++++++++++++++++++++++-
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 02f620d95f7dd2cb2b29cc25e78e7ef404cfad4c..8d6342dde02fd99cfd7d2bedeccf0581ad3504ee 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -484,6 +484,7 @@ enum vcpu_sysreg {
 	CPTR_EL2,	/* Architectural Feature Trap Register (EL2) */
 	HACR_EL2,	/* Hypervisor Auxiliary Control Register */
 	ZCR_EL2,	/* SVE Control Register (EL2) */
+	SMCR_EL2,	/* SME Control Register (EL2) */
 	TTBR0_EL2,	/* Translation Table Base Register 0 (EL2) */
 	TTBR1_EL2,	/* Translation Table Base Register 1 (EL2) */
 	TCR_EL2,	/* Translation Control Register (EL2) */
@@ -521,6 +522,7 @@ enum vcpu_sysreg {
 	VNCR(ACTLR_EL1),/* Auxiliary Control Register */
 	VNCR(CPACR_EL1),/* Coprocessor Access Control */
 	VNCR(ZCR_EL1),	/* SVE Control */
+	VNCR(SMCR_EL1),	/* SME Control */
 	VNCR(TTBR0_EL1),/* Translation Table Base Register 0 */
 	VNCR(TTBR1_EL1),/* Translation Table Base Register 1 */
 	VNCR(TCR_EL1),	/* Translation Control Register */
@@ -998,7 +1000,11 @@ struct kvm_vcpu_arch {
 #define vcpu_vec_max_vq(vcpu, type) sve_vq_from_vl((vcpu)->arch.max_vl[type])
 
 #define vcpu_sve_max_vq(vcpu)	vcpu_vec_max_vq(vcpu, ARM64_VEC_SVE)
+#define vcpu_sme_max_vq(vcpu)	vcpu_vec_max_vq(vcpu, ARM64_VEC_SME)
 
+#define vcpu_max_vl(vcpu) max((vcpu)->arch.max_vl[ARM64_VEC_SVE], \
+			      (vcpu)->arch.max_vl[ARM64_VEC_SME])
+#define vcpu_max_vq(vcpu) sve_vq_from_vl(vcpu_max_vl(vcpu))
 
 #define vcpu_sve_zcr_elx(vcpu)						\
 	(unlikely(is_hyp_ctxt(vcpu)) ? ZCR_EL2 : ZCR_EL1)
diff --git a/arch/arm64/include/asm/vncr_mapping.h b/arch/arm64/include/asm/vncr_mapping.h
index 4f9bbd4d6c2671753124599475e5138bf6b9c749..74fc7400efbc7de6b8dd81a485f1e9d545baf7a9 100644
--- a/arch/arm64/include/asm/vncr_mapping.h
+++ b/arch/arm64/include/asm/vncr_mapping.h
@@ -42,6 +42,7 @@
 #define VNCR_HDFGWTR_EL2	0x1D8
 #define VNCR_ZCR_EL1            0x1E0
 #define VNCR_HAFGRTR_EL2	0x1E8
+#define VNCR_SMCR_EL1		0x1F0
 #define VNCR_TTBR0_EL1          0x200
 #define VNCR_TTBR1_EL1          0x210
 #define VNCR_FAR_EL1            0x220
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1b16716a6d53525fbe694cc8d5d009d72b6ce416..a9429d9d63b54b5b4d4fe365aa6af4d84a256539 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -142,6 +142,7 @@ static bool get_el2_to_el1_mapping(unsigned int reg,
 		MAPPED_EL2_SYSREG(ELR_EL2,     ELR_EL1,	    NULL	     );
 		MAPPED_EL2_SYSREG(SPSR_EL2,    SPSR_EL1,    NULL	     );
 		MAPPED_EL2_SYSREG(ZCR_EL2,     ZCR_EL1,     NULL	     );
+		MAPPED_EL2_SYSREG(SMCR_EL2,    SMCR_EL1,    NULL	     );
 		MAPPED_EL2_SYSREG(CONTEXTIDR_EL2, CONTEXTIDR_EL1, NULL	     );
 	default:
 		return false;
@@ -2405,6 +2406,37 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static unsigned int sme_el2_visibility(const struct kvm_vcpu *vcpu,
+				       const struct sys_reg_desc *rd)
+{
+	return __el2_visibility(vcpu, rd, sme_visibility);
+}
+
+static bool access_smcr_el2(struct kvm_vcpu *vcpu,
+			    struct sys_reg_params *p,
+			    const struct sys_reg_desc *r)
+{
+	unsigned int vq;
+	u64 smcr;
+
+	if (guest_hyp_sve_traps_enabled(vcpu)) {
+		kvm_inject_nested_sve_trap(vcpu);
+		return true;
+	}
+
+	if (!p->is_write) {
+		p->regval = vcpu_read_sys_reg(vcpu, SMCR_EL2);
+		return true;
+	}
+
+	smcr = p->regval;
+	vq = SYS_FIELD_GET(SMCR_ELx, LEN, smcr) + 1;
+	vq = min(vq, vcpu_sme_max_vq(vcpu));
+	vcpu_write_sys_reg(vcpu, SYS_FIELD_PREP(SMCR_ELx, LEN, vq - 1),
+			   SMCR_EL2);
+	return true;
+}
+
 static unsigned int s1poe_visibility(const struct kvm_vcpu *vcpu,
 				     const struct sys_reg_desc *rd)
 {
@@ -2649,7 +2681,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_ZCR_EL1), NULL, reset_val, ZCR_EL1, 0, .visibility = sve_visibility },
 	{ SYS_DESC(SYS_TRFCR_EL1), undef_access },
 	{ SYS_DESC(SYS_SMPRI_EL1), undef_access },
-	{ SYS_DESC(SYS_SMCR_EL1), undef_access },
+	{ SYS_DESC(SYS_SMCR_EL1), NULL, reset_val, SMCR_EL1, 0, .visibility = sme_visibility },
 	{ SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 },
 	{ SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 },
 	{ SYS_DESC(SYS_TCR_EL1), access_vm_reg, reset_val, TCR_EL1, 0 },
@@ -2995,6 +3027,9 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 
 	EL2_REG_VNCR(HCRX_EL2, reset_val, 0),
 
+	EL2_REG_FILTERED(SMCR_EL2, access_smcr_el2, reset_val, 0,
+			 sme_el2_visibility),
+
 	EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),
 	EL2_REG(TTBR1_EL2, access_rw, reset_val, 0),
 	EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1),

-- 
2.39.5