From ea55d5a2cf7c507a9ac03b41716bf1877edad153 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Mon, 10 Jul 2023 19:31:37 +0000 Subject: KVM: arm64: Delete pointless switch statement in kvm_reset_vcpu() The vCPU target hasn't mattered for quite a long time now. Delete the useless switch statement in kvm_reset_vcpu(), which hilariously only had a default case in it. Reviewed-by: Zenghui Yu Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230710193140.1706399-2-oliver.upton@linux.dev --- arch/arm64/kvm/reset.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index bc8556b6f459..7a65a35ee4ac 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -248,21 +248,16 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) } } - switch (vcpu->arch.target) { - default: - if (vcpu_el1_is_32bit(vcpu)) { - pstate = VCPU_RESET_PSTATE_SVC; - } else if (vcpu_has_nv(vcpu)) { - pstate = VCPU_RESET_PSTATE_EL2; - } else { - pstate = VCPU_RESET_PSTATE_EL1; - } - - if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) { - ret = -EINVAL; - goto out; - } - break; + if (vcpu_el1_is_32bit(vcpu)) + pstate = VCPU_RESET_PSTATE_SVC; + else if (vcpu_has_nv(vcpu)) + pstate = VCPU_RESET_PSTATE_EL2; + else + pstate = VCPU_RESET_PSTATE_EL1; + + if (kvm_vcpu_has_pmu(vcpu) && !kvm_arm_support_pmu_v3()) { + ret = -EINVAL; + goto out; } /* Reset core registers */ -- cgit From c8a67729b8a36a5f4857de645ee9808fc99d8618 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Mon, 10 Jul 2023 19:31:38 +0000 Subject: KVM: arm64: Remove pointless check for changed init target At any time there is only a single valid value for KVM_ARM_VCPU_INIT, depending on the current CPU implementation. In all likelihood, this will be the generic ARMv8 target. Drop the pointless check for a changed target value between calls to KVM_ARM_VCPU_INIT and instead rely on the check against kvm_target_cpu(). Signed-off-by: Oliver Upton Reviewed-by: Zenghui Yu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230710193140.1706399-3-oliver.upton@linux.dev --- arch/arm64/kvm/arm.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index c2c14059f6a8..3f844934b9f3 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1212,8 +1212,7 @@ static bool kvm_vcpu_init_changed(struct kvm_vcpu *vcpu, { unsigned long features = init->features[0]; - return !bitmap_equal(vcpu->arch.features, &features, KVM_VCPU_MAX_FEATURES) || - vcpu->arch.target != init->target; + return !bitmap_equal(vcpu->arch.features, &features, KVM_VCPU_MAX_FEATURES); } static int __kvm_vcpu_set_target(struct kvm_vcpu *vcpu, -- cgit From ef98406036769107d5c49a519b31c940910b98d3 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Mon, 10 Jul 2023 19:31:39 +0000 Subject: KVM: arm64: Replace vCPU target with a configuration flag The value of kvm_vcpu_arch::target has been used to determine if a vCPU has actually been initialized. Storing this as an integer is needless at this point, as KVM doesn't do any microarch-specific emulation in the first place. Instead, all we care about is whether or not the vCPU has been initialized. Delete the field in favor of a vCPU configuration flag indicating if KVM_ARM_VCPU_INIT has completed for the vCPU. Reviewed-by: Zenghui Yu Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230710193140.1706399-4-oliver.upton@linux.dev --- arch/arm64/include/asm/kvm_host.h | 5 +++-- arch/arm64/kvm/arm.c | 12 +++++------- arch/arm64/kvm/hyp/nvhe/switch.c | 2 +- 3 files changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 8b6096753740..b53105bccff9 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -567,8 +567,7 @@ struct kvm_vcpu_arch { /* Cache some mmu pages needed inside spinlock regions */ struct kvm_mmu_memory_cache mmu_page_cache; - /* Target CPU and feature flags */ - int target; + /* feature flags */ DECLARE_BITMAP(features, KVM_VCPU_MAX_FEATURES); /* Virtual SError ESR to restore when HCR_EL2.VSE is set */ @@ -669,6 +668,8 @@ struct kvm_vcpu_arch { #define VCPU_SVE_FINALIZED __vcpu_single_flag(cflags, BIT(1)) /* PTRAUTH exposed to guest */ #define GUEST_HAS_PTRAUTH __vcpu_single_flag(cflags, BIT(2)) +/* KVM_ARM_VCPU_INIT completed */ +#define VCPU_INITIALIZED __vcpu_single_flag(cflags, BIT(3)) /* Exception pending */ #define PENDING_EXCEPTION __vcpu_single_flag(iflags, BIT(0)) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 3f844934b9f3..13f1bde0bc2d 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -360,7 +360,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) #endif /* Force users to call KVM_ARM_VCPU_INIT */ - vcpu->arch.target = -1; + vcpu_clear_flag(vcpu, VCPU_INITIALIZED); bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO; @@ -569,7 +569,7 @@ unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu) static int kvm_vcpu_initialized(struct kvm_vcpu *vcpu) { - return vcpu->arch.target >= 0; + return vcpu_get_flag(vcpu, VCPU_INITIALIZED); } /* @@ -1051,7 +1051,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) * invalid. The VMM can try and fix it by issuing a * KVM_ARM_VCPU_INIT if it really wants to. */ - vcpu->arch.target = -1; + vcpu_clear_flag(vcpu, VCPU_INITIALIZED); ret = ARM_EXCEPTION_IL; } @@ -1228,20 +1228,18 @@ static int __kvm_vcpu_set_target(struct kvm_vcpu *vcpu, !bitmap_equal(kvm->arch.vcpu_features, &features, KVM_VCPU_MAX_FEATURES)) goto out_unlock; - vcpu->arch.target = init->target; bitmap_copy(vcpu->arch.features, &features, KVM_VCPU_MAX_FEATURES); /* Now we know what it is, we can reset it. */ ret = kvm_reset_vcpu(vcpu); if (ret) { - vcpu->arch.target = -1; bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); goto out_unlock; } bitmap_copy(kvm->arch.vcpu_features, &features, KVM_VCPU_MAX_FEATURES); set_bit(KVM_ARCH_FLAG_VCPU_FEATURES_CONFIGURED, &kvm->arch.flags); - + vcpu_set_flag(vcpu, VCPU_INITIALIZED); out_unlock: mutex_unlock(&kvm->arch.config_lock); return ret; @@ -1259,7 +1257,7 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, if (ret) return ret; - if (vcpu->arch.target == -1) + if (!kvm_vcpu_initialized(vcpu)) return __kvm_vcpu_set_target(vcpu, init); if (kvm_vcpu_init_changed(vcpu, init)) diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 0a6271052def..b9caac3e7b1d 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -236,7 +236,7 @@ static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code) * KVM_ARM_VCPU_INIT, however, this is likely not possible for * protected VMs. */ - vcpu->arch.target = -1; + vcpu_clear_flag(vcpu, VCPU_INITIALIZED); *exit_code &= BIT(ARM_EXIT_WITH_SERROR_BIT); *exit_code |= ARM_EXCEPTION_IL; } -- cgit From 5346f7e13e5eb134920a14504b6900c6168dd16e Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Mon, 10 Jul 2023 19:31:40 +0000 Subject: KVM: arm64: Always return generic v8 as the preferred target Userspace selecting an implementation-specific vCPU target has been completely useless for a very long time. Let's go whole hog and start returning the generic v8 target across all implementations as the preferred target. Uphold the pre-existing behavior by tolerating either the generic target or an implementation-specific target if the vCPU happens to be running on one of the lucky few parts. Acked-by: Zenghui Yu Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230710193140.1706399-5-oliver.upton@linux.dev --- arch/arm64/include/asm/kvm_host.h | 1 - arch/arm64/kvm/arm.c | 9 +++++---- arch/arm64/kvm/guest.c | 15 --------------- 3 files changed, 5 insertions(+), 20 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index b53105bccff9..ed60277e834a 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -898,7 +898,6 @@ struct kvm_vcpu_stat { u64 exits; }; -void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init); unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu); int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices); int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 13f1bde0bc2d..9ab17ecd76bb 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1250,7 +1250,8 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, { int ret; - if (init->target != kvm_target_cpu()) + if (init->target != KVM_ARM_TARGET_GENERIC_V8 && + init->target != kvm_target_cpu()) return -EINVAL; ret = kvm_vcpu_init_check_features(vcpu, init); @@ -1585,9 +1586,9 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) return kvm_vm_ioctl_set_device_addr(kvm, &dev_addr); } case KVM_ARM_PREFERRED_TARGET: { - struct kvm_vcpu_init init; - - kvm_vcpu_preferred_target(&init); + struct kvm_vcpu_init init = { + .target = KVM_ARM_TARGET_GENERIC_V8, + }; if (copy_to_user(argp, &init, sizeof(init))) return -EFAULT; diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 20280a5233f6..95f6945c4432 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -884,21 +884,6 @@ u32 __attribute_const__ kvm_target_cpu(void) return KVM_ARM_TARGET_GENERIC_V8; } -void kvm_vcpu_preferred_target(struct kvm_vcpu_init *init) -{ - u32 target = kvm_target_cpu(); - - memset(init, 0, sizeof(*init)); - - /* - * For now, we don't return any features. - * In future, we might use features to return target - * specific features available for the preferred - * target type. - */ - init->target = (__u32)target; -} - int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) { return -EINVAL; -- cgit