[GIT PULL] KVM/ARM Urgent fix for 3.16

[GIT PULL] KVM/ARM Urgent fix for 3.16

[Christoffer Dall]

Hi Paolo and Gleb,

Is there any chance you can get this urgent fix (which allows KVM guest
to bring down the entire system on some 64K enabled ARM64 hosts) merged
for 3.16?

The following changes since commit bb18b526a9d8d4a3fe56f234d5013b9f6036978d:

  Merge tag 'signed-for-3.16' of git://github.com/agraf/linux-2.6 into kvm-master (2014-07-08 12:08:58 +0200)

are available in the git repository at:


  git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git tags/kvm-arm-for-3.16-rc7

for you to fetch changes up to 63afbe7a0ac184ef8485dac4914e87b211b5bfaa:

  kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform (2014-07-30 14:35:42 +0200)

---
Will Deacon (1):
  kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform

 virt/kvm/arm/vgic.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

[PATCH] kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform

[Christoffer Dall]

From: Will Deacon <will.deacon@arm.com>

If the physical address of GICV isn't page-aligned, then we end up
creating a stage-2 mapping of the page containing it, which causes us to
map neighbouring memory locations directly into the guest.

As an example, consider a platform with GICV at physical 0x2c02f000
running a 64k-page host kernel. If qemu maps this into the guest at
0x80010000, then guest physical addresses 0x80010000 - 0x8001efff will
map host physical region 0x2c020000 - 0x2c02efff. Accesses to these
physical regions may cause UNPREDICTABLE behaviour, for example, on the
Juno platform this will cause an SError exception to EL3, which brings
down the entire physical CPU resulting in RCU stalls / HYP panics / host
crashing / wasted weeks of debugging.

SBSA recommends that systems alias the 4k GICV across the bounding 64k
region, in which case GICV physical could be described as 0x2c020000 in
the above scenario.

This patch fixes the problem by failing the vgic probe if the physical
base address or the size of GICV aren't page-aligned. Note that this
generated a warning in dmesg about freeing enabled IRQs, so I had to
move the IRQ enabling later in the probe.

Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joel Schopp <joel.schopp@amd.com>
Cc: Don Dutile <ddutile@redhat.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Joel Schopp <joel.schopp@amd.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
 virt/kvm/arm/vgic.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 56ff9be..476d3bf 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1526,17 +1526,33 @@ int kvm_vgic_hyp_init(void)
 		goto out_unmap;
 	}
 
-	kvm_info("%s@%llx IRQ%d\n", vgic_node->name,
-		 vctrl_res.start, vgic_maint_irq);
-	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
-
 	if (of_address_to_resource(vgic_node, 3, &vcpu_res)) {
 		kvm_err("Cannot obtain VCPU resource\n");
 		ret = -ENXIO;
 		goto out_unmap;
 	}
+
+	if (!PAGE_ALIGNED(vcpu_res.start)) {
+		kvm_err("GICV physical address 0x%llx not page aligned\n",
+			(unsigned long long)vcpu_res.start);
+		ret = -ENXIO;
+		goto out_unmap;
+	}
+
+	if (!PAGE_ALIGNED(resource_size(&vcpu_res))) {
+		kvm_err("GICV size 0x%llx not a multiple of page size 0x%lx\n",
+			(unsigned long long)resource_size(&vcpu_res),
+			PAGE_SIZE);
+		ret = -ENXIO;
+		goto out_unmap;
+	}
+
 	vgic_vcpu_base = vcpu_res.start;
 
+	kvm_info("%s@%llx IRQ%d\n", vgic_node->name,
+		 vctrl_res.start, vgic_maint_irq);
+	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
+
 	goto out;
 
 out_unmap:
-- 
2.0.0

[GIT PULL] KVM/ARM Urgent fix for 3.16

[Paolo Bonzini]

Il 30/07/2014 14:55, Christoffer Dall ha scritto:
> Hi Paolo and Gleb,
> 
> Is there any chance you can get this urgent fix (which allows KVM guest
> to bring down the entire system on some 64K enabled ARM64 hosts) merged
> for 3.16?
> 
> The following changes since commit bb18b526a9d8d4a3fe56f234d5013b9f6036978d:
> 
>   Merge tag 'signed-for-3.16' of git://github.com/agraf/linux-2.6 into kvm-master (2014-07-08 12:08:58 +0200)
> 
> are available in the git repository at:
> 
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git tags/kvm-arm-for-3.16-rc7
> 
> for you to fetch changes up to 63afbe7a0ac184ef8485dac4914e87b211b5bfaa:
> 
>   kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform (2014-07-30 14:35:42 +0200)
> 
> ---
> Will Deacon (1):
>   kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform
> 
>  virt/kvm/arm/vgic.c | 24 ++++++++++++++++++++----
>  1 file changed, 20 insertions(+), 4 deletions(-)
> 

I think Gleb is on vacation now, but unfortunately I've already had
enough this year.

I resent the pull request from
git://git.kernel.org/pub/scm/virt/kvm/kvm.git, even though you had CCed
Linus here already.


Paolo

[GIT PULL] KVM/ARM Urgent fix for 3.16

[Christoffer Dall]

On Wed, Jul 30, 2014 at 03:34:11PM +0200, Paolo Bonzini wrote:
> Il 30/07/2014 14:55, Christoffer Dall ha scritto:
> > Hi Paolo and Gleb,
> > 
> > Is there any chance you can get this urgent fix (which allows KVM guest
> > to bring down the entire system on some 64K enabled ARM64 hosts) merged
> > for 3.16?
> > 
> > The following changes since commit bb18b526a9d8d4a3fe56f234d5013b9f6036978d:
> > 
> >   Merge tag 'signed-for-3.16' of git://github.com/agraf/linux-2.6 into kvm-master (2014-07-08 12:08:58 +0200)
> > 
> > are available in the git repository at:
> > 
> > 
> >   git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git tags/kvm-arm-for-3.16-rc7
> > 
> > for you to fetch changes up to 63afbe7a0ac184ef8485dac4914e87b211b5bfaa:
> > 
> >   kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform (2014-07-30 14:35:42 +0200)
> > 
> > ---
> > Will Deacon (1):
> >   kvm: arm64: vgic: fix hyp panic with 64k pages on juno platform
> > 
> >  virt/kvm/arm/vgic.c | 24 ++++++++++++++++++++----
> >  1 file changed, 20 insertions(+), 4 deletions(-)
> > 
> 
> I think Gleb is on vacation now, but unfortunately I've already had
> enough this year.
> 
> I resent the pull request from
> git://git.kernel.org/pub/scm/virt/kvm/kvm.git, even though you had CCed
> Linus here already.
> 
I cc'ed Linus in case you were on vacation and since this is urgent and
last minute.

In any case, thanks to all for dealing with this quickly.

-Christoffer