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Subject[PATCH v2 38/43] arm64: RME: Propagate max SVE vector length from RMM
Date
From: Jean-Philippe Brucker <jean-philippe@linaro.org>

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 <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
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(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index f7ac40ce0caf..902923402f6e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -76,8 +76,8 @@ static inline enum kvm_mode kvm_get_mode(void) { return KVM_MODE_NONE; };

DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);

-extern unsigned int __ro_after_init kvm_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 9c00bcb018f8..be24be001aaa 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -89,6 +89,7 @@ struct realm_rec {
int kvm_init_rme(void);
u32 kvm_realm_ipa_limit(void);
u8 kvm_realm_max_pmu_counters(void);
+unsigned int kvm_realm_sve_max_vl(void);
u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val);

bool kvm_rme_supports_sve(void);
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index f9a47ce71a26..c62fda66cdc5 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -355,7 +355,7 @@ 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 6e6eb4a15095..a90b7c2d35bb 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -45,7 +45,7 @@ static u32 __ro_after_init kvm_ipa_limit;
#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)
{
@@ -73,9 +73,17 @@ 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 1bd97e206846..cd5b74aac092 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -276,6 +276,12 @@ 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(struct kvm_vcpu *vcpu, u64 val)
{
u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);
--
2.34.1

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