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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>
This commit is contained in:
Peter Xu 2017-08-17 13:56:14 +08:00 committed by Michael S. Tsirkin
parent c1800a1627
commit 66a4a0318e
1 changed files with 15 additions and 0 deletions
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15
hw/i386/intel_iommu.c
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@ -957,6 +957,8 @@ static bool vtd_dev_pt_enabled(VTDAddressSpace *as)
static bool vtd_switch_address_space(VTDAddressSpace *as) static bool vtd_switch_address_space(VTDAddressSpace *as)
{ {
bool use_iommu; bool use_iommu;
/* Whether we need to take the BQL on our own */
bool take_bql = !qemu_mutex_iothread_locked();
assert(as); assert(as);
@ -967,6 +969,15 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
VTD_PCI_FUNC(as->devfn), VTD_PCI_FUNC(as->devfn),
use_iommu); 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 */ /* Turn off first then on the other */
if (use_iommu) { if (use_iommu) {
memory_region_set_enabled(&as->sys_alias, false); 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); memory_region_set_enabled(&as->sys_alias, true);
} }
if (take_bql) {
qemu_mutex_unlock_iothread();
}
return use_iommu; return use_iommu;
} }