On 09/07/2024 08:05, Cédric Le Goater wrote:
> On 7/8/24 4:34 PM, Joao Martins wrote:
>> ioctl(iommufd, IOMMU_HWPT_GET_DIRTY_BITMAP, arg) is the UAPI
>> that fetches the bitmap that tells what was dirty in an IOVA
>> range.
>>
>> A single bitmap is allocated and used across all the hwpts
>> sharing an IOAS which is then used in log_sync() to set Qemu
>> global bitmaps.
>>
>> Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
>> ---
>> include/sysemu/iommufd.h | 3 +++
>> backends/iommufd.c | 26 ++++++++++++++++++++++++++
>> hw/vfio/iommufd.c | 34 ++++++++++++++++++++++++++++++++++
>> backends/trace-events | 1 +
>> 4 files changed, 64 insertions(+)
>>
>> diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
>> index 1470377f55ba..223f1ea14e84 100644
>> --- a/include/sysemu/iommufd.h
>> +++ b/include/sysemu/iommufd.h
>> @@ -56,6 +56,9 @@ int iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t
>> dev_id,
>> void *data_ptr, uint32_t *out_hwpt);
>> int iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, uint32_t
>> hwpt_id,
>> bool start);
>> +int iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
>> + uint64_t iova, ram_addr_t size,
>> + uint64_t page_size, uint64_t *data);
>> #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
>> diff --git a/backends/iommufd.c b/backends/iommufd.c
>> index 69daabc27473..b2d3bbd7c31b 100644
>> --- a/backends/iommufd.c
>> +++ b/backends/iommufd.c
>> @@ -257,6 +257,32 @@ int iommufd_backend_set_dirty_tracking(IOMMUFDBackend
>> *be, uint32_t hwpt_id,
>> return ret;
>> }
>> +int iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
>> + uint64_t iova, ram_addr_t size,
>> + uint64_t page_size, uint64_t *data)
>> +{
>> + int ret;
>> + struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap = {
>> + .size = sizeof(get_dirty_bitmap),
>> + .hwpt_id = hwpt_id,
>> + .iova = iova,
>> + .length = size,
>> + .page_size = page_size,
>> + .data = (uintptr_t)data,
>> + };
>> +
>> + ret = ioctl(be->fd, IOMMU_HWPT_GET_DIRTY_BITMAP, &get_dirty_bitmap);
>> + trace_iommufd_backend_get_dirty_bitmap(be->fd, hwpt_id, iova, size,
>> + page_size, ret);
>> + if (ret) {
>> + error_report("IOMMU_HWPT_GET_DIRTY_BITMAP (iova: 0x%"PRIx64
>> + " size: 0x%"PRIx64") failed: %s", iova,
>> + size, strerror(errno));
>> + }
>> +
>> + return !ret ? 0 : -errno;
>> +}
>> +
>> bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
>> uint32_t *type, void *data, uint32_t
>> len,
>> uint64_t *caps, Error **errp)
>> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
>> index 158a98cb3b12..9fad47baed9e 100644
>> --- a/hw/vfio/iommufd.c
>> +++ b/hw/vfio/iommufd.c
>> @@ -25,6 +25,7 @@
>> #include "qemu/cutils.h"
>> #include "qemu/chardev_open.h"
>> #include "pci.h"
>> +#include "exec/ram_addr.h"
>> static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr
>> iova,
>> ram_addr_t size, void *vaddr, bool readonly)
>> @@ -152,6 +153,38 @@ err:
>> return ret;
>> }
>> +static int iommufd_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
>> + VFIOBitmap *vbmap, hwaddr iova,
>> + hwaddr size, Error **errp)
>> +{
>> + VFIOIOMMUFDContainer *container = container_of(bcontainer,
>> + VFIOIOMMUFDContainer,
>> + bcontainer);
>> + int ret;
>> + VFIOIOASHwpt *hwpt;
>> + unsigned long page_size;
>> +
>> + page_size = qemu_real_host_page_size();
>> + QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
>> + if (!iommufd_hwpt_dirty_tracking(hwpt)) {
>> + continue;
>> + }
>> +
>> + ret = iommufd_backend_get_dirty_bitmap(container->be, hwpt->hwpt_id,
>> + iova, size, page_size,
>> + vbmap->bitmap);
>> + if (ret) {
>> + error_setg_errno(errp, ret,
>> + "Failed to get dirty bitmap report, hwpt_id %u,
>> iova: "
>> + "0x%" HWADDR_PRIx ", size: 0x%" HWADDR_PRIx,
>> + hwpt->hwpt_id, iova, size);
>
> This error looks redundant with the one printed out in
> iommufd_backend_get_dirty_bitmap(). Couldn't we add an 'Error **'
> parameter and simply return a bool ?
>
I'll add it.
Just as a sidebar: This is a odd pattern which seems somewhat spread, that
somehow we only care about @errno as something to put on a message, rather then
letting the user know what exact error code it had returned programmatically.
Here in this series it is only important for the device attach so likely doesn't
justify a Error structure enhancement, hence the rest of functions I introduced
here can just adopt bool+errp.
