KVM: arm/arm64: Ensure vcpu target is unset on reset failure

BugLink: https://bugs.launchpad.net/bugs/1838576
[ Upstream commit 811328fc3222f7b55846de0cd0404339e2e1e6d7 ]

A failed KVM_ARM_VCPU_INIT should not set the vcpu target,
as the vcpu target is used by kvm_vcpu_initialized() to
determine if other vcpu ioctls may proceed. We need to set
the target before calling kvm_reset_vcpu(), but if that call
fails, we should then unset it and clear the feature bitmap
while we're at it.

Signed-off-by: Andrew Jones <drjones@redhat.com>
[maz: Simplified patch, completed commit message]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 680c401d0faca7295656952bd5af6718dc81f069..8a5e790d5539610da18dcaf636e7a30e4e6841e1 100644 (file)
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -892,7 +892,7 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level,
 static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
                               const struct kvm_vcpu_init *init)
 {
-       unsigned int i;
+       unsigned int i, ret;
        int phys_target = kvm_target_cpu();
 
        if (init->target != phys_target)
@@ -927,9 +927,14 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
        vcpu->arch.target = phys_target;
 
        /* Now we know what it is, we can reset it. */
-       return kvm_reset_vcpu(vcpu);
-}
+       ret = kvm_reset_vcpu(vcpu);
+       if (ret) {
+               vcpu->arch.target = -1;
+               bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
+       }
 
+       return ret;
+}
 
 static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
                                         struct kvm_vcpu_init *init)