From 9a3cdf26e3363ec5460ebe20c508114fa63bcf26 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Thu, 28 Feb 2019 18:56:50 +0000 Subject: [PATCH] KVM: arm64/sve: Allow userspace to enable SVE for vcpus Now that all the pieces are in place, this patch offers a new flag KVM_ARM_VCPU_SVE that userspace can pass to KVM_ARM_VCPU_INIT to turn on SVE for the guest, on a per-vcpu basis. As part of this, support for initialisation and reset of the SVE vector length set and registers is added in the appropriate places, as well as finally setting the KVM_ARM64_GUEST_HAS_SVE vcpu flag, to turn on the SVE support code. Allocation of the SVE register storage in vcpu->arch.sve_state is deferred until the SVE configuration is finalized, by which time the size of the registers is known. Setting the vector lengths supported by the vcpu is considered configuration of the emulated hardware rather than runtime configuration, so no support is offered for changing the vector lengths available to an existing vcpu across reset. Signed-off-by: Dave Martin Reviewed-by: Julien Thierry Tested-by: zhang.lei Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_host.h | 3 +-- arch/arm64/kvm/reset.c | 43 ++++++++++++++++++++++++++++++- 2 files changed, 43 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 5475cc4df35c..9d57cf8be879 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -49,8 +49,7 @@ #define KVM_MAX_VCPUS VGIC_V3_MAX_CPUS -/* Will be incremented when KVM_ARM_VCPU_SVE is fully implemented: */ -#define KVM_VCPU_MAX_FEATURES 4 +#define KVM_VCPU_MAX_FEATURES 5 #define KVM_REQ_SLEEP \ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index e7f9c06fdbbb..32c5ac0a3872 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -20,10 +20,12 @@ */ #include +#include #include #include #include #include +#include #include #include @@ -37,6 +39,7 @@ #include #include #include +#include /* Maximum phys_shift supported for any VM on this host */ static u32 kvm_ipa_limit; @@ -130,6 +133,27 @@ int kvm_arm_init_arch_resources(void) return 0; } +static int kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu) +{ + if (!system_supports_sve()) + return -EINVAL; + + /* Verify that KVM startup enforced this when SVE was detected: */ + if (WARN_ON(!has_vhe())) + return -EINVAL; + + vcpu->arch.sve_max_vl = kvm_sve_max_vl; + + /* + * Userspace can still customize the vector lengths by writing + * KVM_REG_ARM64_SVE_VLS. Allocation is deferred until + * kvm_arm_vcpu_finalize(), which freezes the configuration. + */ + vcpu->arch.flags |= KVM_ARM64_GUEST_HAS_SVE; + + return 0; +} + /* * Finalize vcpu's maximum SVE vector length, allocating * vcpu->arch.sve_state as necessary. @@ -188,13 +212,20 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) kfree(vcpu->arch.sve_state); } +static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu) +{ + if (vcpu_has_sve(vcpu)) + memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu)); +} + /** * kvm_reset_vcpu - sets core registers and sys_regs to reset value * @vcpu: The VCPU pointer * * This function finds the right table above and sets the registers on * the virtual CPU struct to their architecturally defined reset - * values. + * values, except for registers whose reset is deferred until + * kvm_arm_vcpu_finalize(). * * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT * ioctl or as part of handling a request issued by another VCPU in the PSCI @@ -217,6 +248,16 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) if (loaded) kvm_arch_vcpu_put(vcpu); + if (!kvm_arm_vcpu_sve_finalized(vcpu)) { + if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) { + ret = kvm_vcpu_enable_sve(vcpu); + if (ret) + goto out; + } + } else { + kvm_vcpu_reset_sve(vcpu); + } + switch (vcpu->arch.target) { default: if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) { -- 2.30.2