Commit 97f61225 authored by Jason Wang's avatar Jason Wang Committed by Luis Henriques

kvm: fix zero length mmio searching

commit 8f4216c7 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: default avatarJason Wang <jasowang@redhat.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 0782cb97
......@@ -2803,10 +2803,25 @@ 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;
}
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment