Hi,
On 10/27/20 2:55 PM, Philippe Mathieu-Daudé wrote:
> qemu_vfio_pci_map_bar() calls mmap(), and mmap(2) states:
>
> 'offset' must be a multiple of the page size as returned
> by sysconf(_SC_PAGE_SIZE).
>
> In commit f68453237b9 we started to use an offset of 4K which
> broke this contract on Aarch64 arch.
>
> Fix by mapping at offset 0, and and accessing doorbells at offset=4K.
>
> Fixes: f68453237b9 ("block/nvme: Map doorbells pages write-only")
> Reported-by: Eric Auger <eric.au...@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Eric
> ---
> block/nvme.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/block/nvme.c b/block/nvme.c
> index c1c52bae44f..ff645eefe6a 100644
> --- a/block/nvme.c
> +++ b/block/nvme.c
> @@ -94,6 +94,7 @@ typedef struct {
> struct BDRVNVMeState {
> AioContext *aio_context;
> QEMUVFIOState *vfio;
> + void *bar0_wo_map;
> /* Memory mapped registers */
> volatile struct {
> uint32_t sq_tail;
> @@ -778,8 +779,10 @@ static int nvme_init(BlockDriverState *bs, const char
> *device, int namespace,
> }
> }
>
> - s->doorbells = qemu_vfio_pci_map_bar(s->vfio, 0, sizeof(NvmeBar),
> - NVME_DOORBELL_SIZE, PROT_WRITE,
> errp);
> + s->bar0_wo_map = qemu_vfio_pci_map_bar(s->vfio, 0, 0,
> + sizeof(NvmeBar) +
> NVME_DOORBELL_SIZE,
> + PROT_WRITE, errp);
> + s->doorbells = (void *)((uintptr_t)s->bar0_wo_map + sizeof(NvmeBar));
> if (!s->doorbells) {
> ret = -EINVAL;
> goto out;
> @@ -913,8 +916,8 @@ static void nvme_close(BlockDriverState *bs)
> &s->irq_notifier[MSIX_SHARED_IRQ_IDX],
> false, NULL, NULL);
> event_notifier_cleanup(&s->irq_notifier[MSIX_SHARED_IRQ_IDX]);
> - qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->doorbells,
> - sizeof(NvmeBar), NVME_DOORBELL_SIZE);
> + qemu_vfio_pci_unmap_bar(s->vfio, 0, s->bar0_wo_map,
> + 0, sizeof(NvmeBar) + NVME_DOORBELL_SIZE);
> qemu_vfio_close(s->vfio);
>
> g_free(s->device);
>
