[v6,37/43] arm64: RME: Propagate max SVE vector length from RMM

Commit Message

Steven Price Dec. 12, 2024, 3:56 p.m. UTC

From: Jean-Philippe Brucker <[e-mail]>

RMM provides the maximum vector length it supports for a guest in its
feature register. Make it visible to the rest of KVM and to userspace
via KVM_REG_ARM64_SVE_VLS.

Signed-off-by: Jean-Philippe Brucker <[e-mail]>
Signed-off-by: Steven Price <[e-mail]>
---
 arch/arm64/include/asm/kvm_host.h |  2 +-
 arch/arm64/include/asm/kvm_rme.h  |  1 +
 arch/arm64/kvm/guest.c            |  2 +-
 arch/arm64/kvm/reset.c            | 12 ++++++++++--
 arch/arm64/kvm/rme.c              |  6 ++++++
 5 files changed, 19 insertions(+), 4 deletions(-)

Patch

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 220195c727ef..5b16e7d61de8 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -75,9 +75,9 @@  enum kvm_mode kvm_get_mode(void);
 static inline enum kvm_mode kvm_get_mode(void) { return KVM_MODE_NONE; };
 #endif
 
-extern unsigned int __ro_after_init kvm_sve_max_vl;
 extern unsigned int __ro_after_init kvm_host_sve_max_vl;
 int __init kvm_arm_init_sve(void);
+unsigned int kvm_sve_get_max_vl(struct kvm *kvm);
 
 u32 __attribute_const__ kvm_target_cpu(void);
 void kvm_reset_vcpu(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 7839ef81c20e..4b2e21d5f37e 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -85,6 +85,7 @@  void kvm_init_rme(void);
 u32 kvm_realm_ipa_limit(void);
 u32 kvm_realm_vgic_nr_lr(void);
 u8 kvm_realm_max_pmu_counters(void);
+unsigned int kvm_realm_sve_max_vl(void);
 
 u64 kvm_realm_reset_id_aa64dfr0_el1(const struct kvm_vcpu *vcpu, u64 val);
 
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 60756b4c18fc..429c8f10b76a 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -377,7 +377,7 @@  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_sve_max_vl))
+	if (max_vq > sve_vq_from_vl(kvm_sve_get_max_vl(vcpu->kvm)))
 		return -EINVAL;
 
 	/*
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 16a5d11fc75a..26134c904865 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -46,7 +46,7 @@  unsigned int __ro_after_init kvm_host_sve_max_vl;
 #define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
 				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)
 
-unsigned int __ro_after_init kvm_sve_max_vl;
+static unsigned int __ro_after_init kvm_sve_max_vl;
 
 int __init kvm_arm_init_sve(void)
 {
@@ -76,9 +76,17 @@  int __init kvm_arm_init_sve(void)
 	return 0;
 }
 
+unsigned int kvm_sve_get_max_vl(struct kvm *kvm)
+{
+	if (kvm_is_realm(kvm))
+		return kvm_realm_sve_max_vl();
+	else
+		return kvm_sve_max_vl;
+}
+
 static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
 {
-	vcpu->arch.sve_max_vl = kvm_sve_max_vl;
+	vcpu->arch.sve_max_vl = kvm_sve_get_max_vl(vcpu->kvm);
 
 	/*
 	 * Userspace can still customize the vector lengths by writing
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 1230550e2a71..39dbc19e4a42 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -68,6 +68,12 @@  u8 kvm_realm_max_pmu_counters(void)
 	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS);
 }
 
+unsigned int kvm_realm_sve_max_vl(void)
+{
+	return sve_vl_from_vq(u64_get_bits(rmm_feat_reg0,
+					   RMI_FEATURE_REGISTER_0_SVE_VL) + 1);
+}
+
 u64 kvm_realm_reset_id_aa64dfr0_el1(const struct kvm_vcpu *vcpu, u64 val)
 {
 	u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);