From: Oliver Upton Date: Wed, 20 Sep 2023 19:50:29 +0000 (+0000) Subject: KVM: arm64: Add generic check for system-supported vCPU features X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ef150908b6bd80a54126dbec324bd63a24a5628a;p=linux.git KVM: arm64: Add generic check for system-supported vCPU features To date KVM has relied on kvm_reset_vcpu() failing when the vCPU feature flags are unsupported by the system. This is a bit messy since kvm_reset_vcpu() is called at runtime outside of the KVM_ARM_VCPU_INIT ioctl when it is expected to succeed. Further complicating the matter is that kvm_reset_vcpu() must tolerate be idemptotent to the config_lock, as it isn't consistently called with the lock held. Prepare to move feature compatibility checks out of kvm_reset_vcpu() with a 'generic' check that compares the user-provided flags with a computed maximum feature set for the system. Reviewed-by: Philippe Mathieu-Daudé Link: https://lore.kernel.org/r/20230920195036.1169791-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 4866b3f7b4ea3..8b5094343f84b 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1190,6 +1190,16 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, return -EINVAL; } +static unsigned long system_supported_vcpu_features(void) +{ + unsigned long features = KVM_VCPU_VALID_FEATURES; + + if (!cpus_have_final_cap(ARM64_HAS_32BIT_EL1)) + clear_bit(KVM_ARM_VCPU_EL1_32BIT, &features); + + return features; +} + static int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu, const struct kvm_vcpu_init *init) { @@ -1204,12 +1214,12 @@ static int kvm_vcpu_init_check_features(struct kvm_vcpu *vcpu, return -ENOENT; } + if (features & ~system_supported_vcpu_features()) + return -EINVAL; + if (!test_bit(KVM_ARM_VCPU_EL1_32BIT, &features)) return 0; - if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1)) - return -EINVAL; - /* MTE is incompatible with AArch32 */ if (kvm_has_mte(vcpu->kvm)) return -EINVAL;