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authorPeter Xu <peterx@redhat.com>2017-08-17 13:56:14 +0800
committerMichael S. Tsirkin <mst@redhat.com>2017-09-08 16:15:17 +0300
commit66a4a0318e6b9539505491e4576fb93a708095d8 (patch)
treefcb988023d2427fa216f90dca88a3ab9e56167ef /hw
parentc1800a16276582f65807f464a6ab0b7c88a1c16e (diff)
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intel_iommu: fix missing BQL in pt fast path
In vtd_switch_address_space() we did the memory region switch, however it's possible that the caller of it has not taken the BQL at all. Make sure we have it. CC: Paolo Bonzini <pbonzini@redhat.com> CC: Jason Wang <jasowang@redhat.com> CC: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/i386/intel_iommu.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index a7bf87a..3a5bb0b 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -957,6 +957,8 @@ static bool vtd_dev_pt_enabled(VTDAddressSpace *as)
static bool vtd_switch_address_space(VTDAddressSpace *as)
{
bool use_iommu;
+ /* Whether we need to take the BQL on our own */
+ bool take_bql = !qemu_mutex_iothread_locked();
assert(as);
@@ -967,6 +969,15 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
VTD_PCI_FUNC(as->devfn),
use_iommu);
+ /*
+ * It's possible that we reach here without BQL, e.g., when called
+ * from vtd_pt_enable_fast_path(). However the memory APIs need
+ * it. We'd better make sure we have had it already, or, take it.
+ */
+ if (take_bql) {
+ qemu_mutex_lock_iothread();
+ }
+
/* Turn off first then on the other */
if (use_iommu) {
memory_region_set_enabled(&as->sys_alias, false);
@@ -976,6 +987,10 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
memory_region_set_enabled(&as->sys_alias, true);
}
+ if (take_bql) {
+ qemu_mutex_unlock_iothread();
+ }
+
return use_iommu;
}