Commit 66a4a031 authored by Peter Xu's avatar Peter Xu Committed by Michael S. Tsirkin
Browse files

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: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent c1800a16

hw/i386/intel_iommu.c

+15 −0
Original line number Diff line number Diff line
@@ -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;

}