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 <yuzenghui@huawei.com>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230710193140.1706399-4-oliver.upton@linux.dev

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 8b60967..b53105b 100644 (file)
--- 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 3f84493..13f1bde 100644 (file)
--- 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 0a62710..b9caac3 100644 (file)
--- 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;
        }