path: root/virt/kvm/arm/vgic/vgic-its.c
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authorMarc Zyngier <marc.zyngier@arm.com>2016-07-17 11:48:47 +0100
committerMarc Zyngier <marc.zyngier@arm.com>2016-07-18 18:15:18 +0100
commitd6c7f865f00adf98ca79712167fb0f1b9dccb272 (patch)
treeeba4cdf8b80f67d46212e425b335214aafdeb1cf /virt/kvm/arm/vgic/vgic-its.c
parent333a53ff7fb9d836ff4a2b7f266ac9b2bb85e873 (diff)
KVM: arm64: vgic-its: Fix L2 entry validation for indirect tables
When checking that the storage address of a device entry is valid, it is critical to compute the actual address of the entry, rather than relying on the beginning of the page to match a CPU page of the same size: for example, if the guest places the table at the last 64kB boundary of RAM, but RAM size isn't a multiple of 64kB... Fix this by computing the actual offset of the device ID in the L2 page, and check the corresponding GFN. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'virt/kvm/arm/vgic/vgic-its.c')
1 files changed, 6 insertions, 1 deletions
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 4943d6aebdd1..2faf1f458e8a 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -727,7 +727,12 @@ static bool vgic_its_check_device_id(struct kvm *kvm, struct vgic_its *its,
* Any address beyond our supported 48 bits of PA will be caught
* by the actual check in the final step.
- gfn = (indirect_ptr & GENMASK_ULL(51, 16)) >> PAGE_SHIFT;
+ indirect_ptr &= GENMASK_ULL(51, 16);
+ /* Find the address of the actual entry */
+ index = device_id % (SZ_64K / GITS_BASER_ENTRY_SIZE(r));
+ indirect_ptr += index * GITS_BASER_ENTRY_SIZE(r);
+ gfn = indirect_ptr >> PAGE_SHIFT;
return kvm_is_visible_gfn(kvm, gfn);