This is a note to let you know that I've just added the patch titled
KVM: arm64: vgic: Simplify kvm_vgic_destroy()
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-arm64-vgic-simplify-kvm_vgic_destroy.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 01ad29d224ff73bc4e16e0ef9ece17f28598c4a4 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@xxxxxxxxxx>
Date: Thu, 7 Dec 2023 15:11:57 +0000
Subject: KVM: arm64: vgic: Simplify kvm_vgic_destroy()
From: Marc Zyngier <maz@xxxxxxxxxx>
commit 01ad29d224ff73bc4e16e0ef9ece17f28598c4a4 upstream.
When destroying a vgic, we have rather cumbersome rules about
when slots_lock and config_lock are held, resulting in fun
buglets.
The first port of call is to simplify kvm_vgic_map_resources()
so that there is only one call to kvm_vgic_destroy() instead of
two, with the second only holding half of the locks.
For that, we kill the non-locking primitive and move the call
outside of the locking altogether. This doesn't change anything
(we re-acquire the locks and teardown the whole vgic), and
simplifies the code significantly.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231207151201.3028710-2-maz@xxxxxxxxxx
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kvm/vgic/vgic-init.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -382,26 +382,24 @@ void kvm_vgic_vcpu_destroy(struct kvm_vc
vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
}
-static void __kvm_vgic_destroy(struct kvm *kvm)
+void kvm_vgic_destroy(struct kvm *kvm)
{
struct kvm_vcpu *vcpu;
unsigned long i;
- lockdep_assert_held(&kvm->arch.config_lock);
+ mutex_lock(&kvm->slots_lock);
vgic_debug_destroy(kvm);
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_vgic_vcpu_destroy(vcpu);
+ mutex_lock(&kvm->arch.config_lock);
+
kvm_vgic_dist_destroy(kvm);
-}
-void kvm_vgic_destroy(struct kvm *kvm)
-{
- mutex_lock(&kvm->arch.config_lock);
- __kvm_vgic_destroy(kvm);
mutex_unlock(&kvm->arch.config_lock);
+ mutex_unlock(&kvm->slots_lock);
}
/**
@@ -469,25 +467,26 @@ int kvm_vgic_map_resources(struct kvm *k
type = VGIC_V3;
}
- if (ret) {
- __kvm_vgic_destroy(kvm);
+ if (ret)
goto out;
- }
+
dist->ready = true;
dist_base = dist->vgic_dist_base;
mutex_unlock(&kvm->arch.config_lock);
ret = vgic_register_dist_iodev(kvm, dist_base, type);
- if (ret) {
+ if (ret)
kvm_err("Unable to register VGIC dist MMIO regions\n");
- kvm_vgic_destroy(kvm);
- }
- mutex_unlock(&kvm->slots_lock);
- return ret;
+ goto out_slots;
out:
mutex_unlock(&kvm->arch.config_lock);
+out_slots:
mutex_unlock(&kvm->slots_lock);
+
+ if (ret)
+ kvm_vgic_destroy(kvm);
+
return ret;
}
Patches currently in stable-queue which might be from maz@xxxxxxxxxx are
queue-6.1/kvm-arm64-vgic-force-vcpu-vgic-teardown-on-vcpu-destroy.patch
queue-6.1/kvm-arm64-vgic-add-a-non-locking-primitive-for-kvm_vgic_vcpu_destroy.patch
queue-6.1/kvm-arm64-vgic-simplify-kvm_vgic_destroy.patch
