On Sat, Feb 24, 2018 at 09:30:12AM +0100, Jan Kiszka wrote: > From: Jan Kiszka <jan.kis...@siemens.com> > > Xen is doing this [1] and currently triggers an abort. > > [1] > http://xenbits.xenproject.org/gitweb/?p=xen.git;a=blob;f=xen/drivers/passthrough/vtd/iommu.c;h=daaed0abbdd06b6ba3d948ea103aadf02651e83c;hb=refs/heads/master#l1108 > > Reported-by: Luis Lloret <luis_llo...@mentor.com> > Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
Thanks, Jan. Reviewed-by: Peter Xu <pet...@redhat.com> > --- > hw/i386/intel_iommu.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 2e841cde27..fb31de9416 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -2129,8 +2129,15 @@ static void vtd_mem_write(void *opaque, hwaddr addr, > > /* Fault Event Address Register, 32-bit */ > case DMAR_FEADDR_REG: > - assert(size == 4); > - vtd_set_long(s, addr, val); > + if (size == 4) { > + vtd_set_long(s, addr, val); > + } else { > + /* > + * While the register is 32-bit only, some guests (Xen...) write > to > + * it with 64-bit. > + */ > + vtd_set_quad(s, addr, val); > + } > break; > > /* Fault Event Upper Address Register, 32-bit */ -- Peter Xu