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authorJason Wang <jasowang@redhat.com>2015-09-15 14:41:57 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-22 14:43:10 -0700
commit989bbb3a4c25d9e21a791a4d23cf24610270db63 (patch)
tree429ae0396de08a899837489fc3e35aefe43d2669 /virt
parent87f3ae1f34a06fb5296a4b0d763737171c3f2d65 (diff)
downloadlinux-linaro-stable-989bbb3a4c25d9e21a791a4d23cf24610270db63.tar.gz
kvm: fix zero length mmio searching
commit 8f4216c7d28976f7ec1b2bcbfa0a9f787133c45e upstream. Currently, if we had a zero length mmio eventfd assigned on KVM_MMIO_BUS. It will never be found by kvm_io_bus_cmp() since it always compares the kvm_io_range() with the length that guest wrote. This will cause e.g for vhost, kick will be trapped by qemu userspace instead of vhost. Fixing this by using zero length if an iodevice is zero length. Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 90977418aeb6..85422985235f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2935,10 +2935,25 @@ static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1,
const struct kvm_io_range *r2)
{
- if (r1->addr < r2->addr)
+ gpa_t addr1 = r1->addr;
+ gpa_t addr2 = r2->addr;
+
+ if (addr1 < addr2)
return -1;
- if (r1->addr + r1->len > r2->addr + r2->len)
+
+ /* If r2->len == 0, match the exact address. If r2->len != 0,
+ * accept any overlapping write. Any order is acceptable for
+ * overlapping ranges, because kvm_io_bus_get_first_dev ensures
+ * we process all of them.
+ */
+ if (r2->len) {
+ addr1 += r1->len;
+ addr2 += r2->len;
+ }
+
+ if (addr1 > addr2)
return 1;
+
return 0;
}