> Subject: Re: [PATCH] xen/swiotlb: correct the check for > xen_destroy_contiguous_region > > On 28.04.20 09:33, peng....@nxp.com wrote: > > From: Peng Fan <peng....@nxp.com> > > > > When booting xen on i.MX8QM, met: > > " > > [ 3.602128] Unable to handle kernel paging request at virtual address > 0000000000272d40 > > [ 3.610804] Mem abort info: > > [ 3.613905] ESR = 0x96000004 > > [ 3.617332] EC = 0x25: DABT (current EL), IL = 32 bits > > [ 3.623211] SET = 0, FnV = 0 > > [ 3.626628] EA = 0, S1PTW = 0 > > [ 3.630128] Data abort info: > > [ 3.633362] ISV = 0, ISS = 0x00000004 > > [ 3.637630] CM = 0, WnR = 0 > > [ 3.640955] [0000000000272d40] user address but active_mm is > swapper > > [ 3.647983] Internal error: Oops: 96000004 [#1] PREEMPT SMP > > [ 3.654137] Modules linked in: > > [ 3.677285] Hardware name: Freescale i.MX8QM MEK (DT) > > [ 3.677302] Workqueue: events deferred_probe_work_func > > [ 3.684253] imx6q-pcie 5f000000.pcie: PCI host bridge to bus 0000:00 > > [ 3.688297] pstate: 60000005 (nZCv daif -PAN -UAO) > > [ 3.688310] pc : xen_swiotlb_free_coherent+0x180/0x1c0 > > [ 3.693993] pci_bus 0000:00: root bus resource [bus 00-ff] > > [ 3.701002] lr : xen_swiotlb_free_coherent+0x44/0x1c0 > > " > > > > In xen_swiotlb_alloc_coherent, if !(dev_addr + size - 1 <= dma_mask) > > or range_straddles_page_boundary(phys, size) are true, it will create > > contiguous region. So when free, we need to free contiguous region use > > upper check condition. > > No, this will break PV guests on x86.
Could you share more details why alloc and free not matching for the check? Thanks, Peng. > > I think there is something wrong with your setup in combination with the ARM > xen_create_contiguous_region() implementation. > > Stefano? > > > Juergen > > > > > Signed-off-by: Peng Fan <peng....@nxp.com> > > --- > > drivers/xen/swiotlb-xen.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > > index b6d27762c6f8..ab96e468584f 100644 > > --- a/drivers/xen/swiotlb-xen.c > > +++ b/drivers/xen/swiotlb-xen.c > > @@ -346,8 +346,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, > size_t size, void *vaddr, > > /* Convert the size to actually allocated. */ > > size = 1UL << (order + XEN_PAGE_SHIFT); > > > > - if (!WARN_ON((dev_addr + size - 1 > dma_mask) || > > - range_straddles_page_boundary(phys, size)) && > > + if (((dev_addr + size - 1 > dma_mask) || > > + range_straddles_page_boundary(phys, size)) && > > TestClearPageXenRemapped(virt_to_page(vaddr))) > > xen_destroy_contiguous_region(phys, order); > > > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
