* [PATCH v2 1/3] vfio/container: Support unmap all in one ioctl()
2025-10-09 4:01 [PATCH v2 0/3] Optimize unmap_all with one ioctl() Zhenzhong Duan
@ 2025-10-09 4:01 ` Zhenzhong Duan
2025-10-09 4:01 ` [PATCH v2 2/3] vfio/iommufd: " Zhenzhong Duan
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Zhenzhong Duan @ 2025-10-09 4:01 UTC (permalink / raw)
To: qemu-devel; +Cc: alex.williamson, clg, eric.auger, levon, Zhenzhong Duan
VFIO type1 kernel uAPI supports unmapping whole address space in one call
since commit c19650995374 ("vfio/type1: implement unmap all"). Use the
unmap_all variant whenever it's supported in kernel.
Opportunistically pass VFIOLegacyContainer pointer in low level function
vfio_legacy_dma_unmap_one().
Co-developed-by: John Levon <levon@movementarian.org>
Signed-off-by: John Levon <levon@movementarian.org>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
include/hw/vfio/vfio-container-legacy.h | 1 +
hw/vfio/container-legacy.c | 38 ++++++++++++++-----------
2 files changed, 23 insertions(+), 16 deletions(-)
diff --git a/include/hw/vfio/vfio-container-legacy.h b/include/hw/vfio/vfio-container-legacy.h
index 74a72df018..ffd594e80d 100644
--- a/include/hw/vfio/vfio-container-legacy.h
+++ b/include/hw/vfio/vfio-container-legacy.h
@@ -30,6 +30,7 @@ struct VFIOLegacyContainer {
int fd; /* /dev/vfio/vfio, empowered by the attached groups */
unsigned iommu_type;
+ bool unmap_all_supported;
QLIST_HEAD(, VFIOGroup) group_list;
VFIOContainerCPR cpr;
};
diff --git a/hw/vfio/container-legacy.c b/hw/vfio/container-legacy.c
index a3615d7b5d..8e9639603e 100644
--- a/hw/vfio/container-legacy.c
+++ b/hw/vfio/container-legacy.c
@@ -121,14 +121,14 @@ unmap_exit:
return ret;
}
-static int vfio_legacy_dma_unmap_one(const VFIOContainer *bcontainer,
+static int vfio_legacy_dma_unmap_one(const VFIOLegacyContainer *container,
hwaddr iova, uint64_t size,
- IOMMUTLBEntry *iotlb)
+ uint32_t flags, IOMMUTLBEntry *iotlb)
{
- const VFIOLegacyContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
+ const VFIOContainer *bcontainer = VFIO_IOMMU(container);
struct vfio_iommu_type1_dma_unmap unmap = {
.argsz = sizeof(unmap),
- .flags = 0,
+ .flags = flags,
.iova = iova,
.size = size,
};
@@ -170,25 +170,28 @@ static int vfio_legacy_dma_unmap(const VFIOContainer *bcontainer,
hwaddr iova, uint64_t size,
IOMMUTLBEntry *iotlb, bool unmap_all)
{
+ const VFIOLegacyContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
+ uint32_t flags = 0;
int ret;
if (unmap_all) {
- /* The unmap ioctl doesn't accept a full 64-bit span. */
- Int128 llsize = int128_rshift(int128_2_64(), 1);
-
- ret = vfio_legacy_dma_unmap_one(bcontainer, 0, int128_get64(llsize),
- iotlb);
+ if (container->unmap_all_supported) {
+ flags = VFIO_DMA_UNMAP_FLAG_ALL;
+ } else {
+ /* The unmap ioctl doesn't accept a full 64-bit span. */
+ Int128 llsize = int128_rshift(int128_2_64(), 1);
+ size = int128_get64(llsize);
+
+ ret = vfio_legacy_dma_unmap_one(container, 0, size, flags, iotlb);
+ if (ret) {
+ return ret;
+ }
- if (ret == 0) {
- ret = vfio_legacy_dma_unmap_one(bcontainer, int128_get64(llsize),
- int128_get64(llsize), iotlb);
+ iova = size;
}
-
- } else {
- ret = vfio_legacy_dma_unmap_one(bcontainer, iova, size, iotlb);
}
- return ret;
+ return vfio_legacy_dma_unmap_one(container, iova, size, flags, iotlb);
}
static int vfio_legacy_dma_map(const VFIOContainer *bcontainer, hwaddr iova,
@@ -519,6 +522,9 @@ static bool vfio_legacy_setup(VFIOContainer *bcontainer, Error **errp)
vfio_get_info_iova_range(info, bcontainer);
+ ret = ioctl(container->fd, VFIO_CHECK_EXTENSION, VFIO_UNMAP_ALL);
+ container->unmap_all_supported = !!ret;
+
vfio_get_iommu_info_migration(container, info);
return true;
}
--
2.47.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 2/3] vfio/iommufd: Support unmap all in one ioctl()
2025-10-09 4:01 [PATCH v2 0/3] Optimize unmap_all with one ioctl() Zhenzhong Duan
2025-10-09 4:01 ` [PATCH v2 1/3] vfio/container: Support unmap all in " Zhenzhong Duan
@ 2025-10-09 4:01 ` Zhenzhong Duan
2025-10-09 4:01 ` [PATCH v2 3/3] vfio/listener: Add an assertion for unmap_all Zhenzhong Duan
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Zhenzhong Duan @ 2025-10-09 4:01 UTC (permalink / raw)
To: qemu-devel; +Cc: alex.williamson, clg, eric.auger, levon, Zhenzhong Duan
IOMMUFD kernel uAPI supports unmapping whole address space in one call with
[iova, size] set to [0, UINT64_MAX], this can simplify iommufd_cdev_unmap()
a bit. See iommufd_ioas_unmap() in kernel for details.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
hw/vfio/iommufd.c | 15 +--------------
1 file changed, 1 insertion(+), 14 deletions(-)
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 68470d552e..336f8fdb04 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -62,21 +62,8 @@ static int iommufd_cdev_unmap(const VFIOContainer *bcontainer,
{
const VFIOIOMMUFDContainer *container = VFIO_IOMMU_IOMMUFD(bcontainer);
- /* unmap in halves */
if (unmap_all) {
- Int128 llsize = int128_rshift(int128_2_64(), 1);
- int ret;
-
- ret = iommufd_backend_unmap_dma(container->be, container->ioas_id,
- 0, int128_get64(llsize));
-
- if (ret == 0) {
- ret = iommufd_backend_unmap_dma(container->be, container->ioas_id,
- int128_get64(llsize),
- int128_get64(llsize));
- }
-
- return ret;
+ size = UINT64_MAX;
}
/* TODO: Handle dma_unmap_bitmap with iotlb args (migration) */
--
2.47.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 3/3] vfio/listener: Add an assertion for unmap_all
2025-10-09 4:01 [PATCH v2 0/3] Optimize unmap_all with one ioctl() Zhenzhong Duan
2025-10-09 4:01 ` [PATCH v2 1/3] vfio/container: Support unmap all in " Zhenzhong Duan
2025-10-09 4:01 ` [PATCH v2 2/3] vfio/iommufd: " Zhenzhong Duan
@ 2025-10-09 4:01 ` Zhenzhong Duan
2025-10-09 7:35 ` [PATCH v2 0/3] Optimize unmap_all with one ioctl() Cédric Le Goater
2025-10-09 8:05 ` Cédric Le Goater
4 siblings, 0 replies; 6+ messages in thread
From: Zhenzhong Duan @ 2025-10-09 4:01 UTC (permalink / raw)
To: qemu-devel; +Cc: alex.williamson, clg, eric.auger, levon, Zhenzhong Duan
Currently the maximum of iommu address space is 64bit. So when a maximum
iommu memory section is deleted, it's in scope [0, 2^64). Add a
assertion for that.
Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
hw/vfio/listener.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index c6bb58f520..62766d8c46 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -715,6 +715,7 @@ static void vfio_listener_region_del(MemoryListener *listener,
bool unmap_all = false;
if (int128_eq(llsize, int128_2_64())) {
+ assert(!iova);
unmap_all = true;
llsize = int128_zero();
}
--
2.47.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v2 0/3] Optimize unmap_all with one ioctl()
2025-10-09 4:01 [PATCH v2 0/3] Optimize unmap_all with one ioctl() Zhenzhong Duan
` (2 preceding siblings ...)
2025-10-09 4:01 ` [PATCH v2 3/3] vfio/listener: Add an assertion for unmap_all Zhenzhong Duan
@ 2025-10-09 7:35 ` Cédric Le Goater
2025-10-09 8:05 ` Cédric Le Goater
4 siblings, 0 replies; 6+ messages in thread
From: Cédric Le Goater @ 2025-10-09 7:35 UTC (permalink / raw)
To: Zhenzhong Duan, qemu-devel; +Cc: alex.williamson, eric.auger, levon
On 10/9/25 06:01, Zhenzhong Duan wrote:
> Currently unmap_all is split into two ioctl() with each unmap half of
> the whole iova space.
>
> IOMMUFD supports unmap_all ioctl() from beginning, after kernel commit
> c19650995374 ("vfio/type1: implement unmap all") added same support
> for VFIO type1, the split becomes unnecessary.
>
> So optimize the code to only do one ioctl() to unmap_all for both
> backends.
>
> Test:
> In order to trigger unmap_all request, I have to fake a unmap_all request
> on x86. Maybe it's easy to trigger unmap_all with other arch, e.g., arm smmu,
> but for x86, iommu memory region is split by iommu_ir, unmap_all isn't
> triggered by default. See
> https://github.com/yiliu1765/qemu/commit/7afc7adac8fa601abd978b821c86e90e073d31ba
> for details.
>
> Thanks
> Zhenzhong
>
> Changelog:
> v2:
> - check unmap_all_supported instead of ioctl() for every unmap_all (John Levon)
> - make assertion a separate patch (Cedric)
> - pass VFIOLegacyContainer pointer in vfio_legacy_dma_unmap_one() (Cedric)
>
> Zhenzhong Duan (3):
> vfio/container: Support unmap all in one ioctl()
> vfio/iommufd: Support unmap all in one ioctl()
> vfio/listener: Add an assertion for unmap_all
>
> include/hw/vfio/vfio-container-legacy.h | 1 +
> hw/vfio/container-legacy.c | 38 ++++++++++++++-----------
> hw/vfio/iommufd.c | 15 +---------
> hw/vfio/listener.c | 1 +
> 4 files changed, 25 insertions(+), 30 deletions(-)
>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Thanks,
C.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2 0/3] Optimize unmap_all with one ioctl()
2025-10-09 4:01 [PATCH v2 0/3] Optimize unmap_all with one ioctl() Zhenzhong Duan
` (3 preceding siblings ...)
2025-10-09 7:35 ` [PATCH v2 0/3] Optimize unmap_all with one ioctl() Cédric Le Goater
@ 2025-10-09 8:05 ` Cédric Le Goater
4 siblings, 0 replies; 6+ messages in thread
From: Cédric Le Goater @ 2025-10-09 8:05 UTC (permalink / raw)
To: Zhenzhong Duan, qemu-devel; +Cc: alex.williamson, eric.auger, levon
On 10/9/25 06:01, Zhenzhong Duan wrote:
> Currently unmap_all is split into two ioctl() with each unmap half of
> the whole iova space.
>
> IOMMUFD supports unmap_all ioctl() from beginning, after kernel commit
> c19650995374 ("vfio/type1: implement unmap all") added same support
> for VFIO type1, the split becomes unnecessary.
>
> So optimize the code to only do one ioctl() to unmap_all for both
> backends.
>
> Test:
> In order to trigger unmap_all request, I have to fake a unmap_all request
> on x86. Maybe it's easy to trigger unmap_all with other arch, e.g., arm smmu,
> but for x86, iommu memory region is split by iommu_ir, unmap_all isn't
> triggered by default. See
> https://github.com/yiliu1765/qemu/commit/7afc7adac8fa601abd978b821c86e90e073d31ba
> for details.
>
> Thanks
> Zhenzhong
>
> Changelog:
> v2:
> - check unmap_all_supported instead of ioctl() for every unmap_all (John Levon)
> - make assertion a separate patch (Cedric)
> - pass VFIOLegacyContainer pointer in vfio_legacy_dma_unmap_one() (Cedric)
>
> Zhenzhong Duan (3):
> vfio/container: Support unmap all in one ioctl()
> vfio/iommufd: Support unmap all in one ioctl()
> vfio/listener: Add an assertion for unmap_all
>
> include/hw/vfio/vfio-container-legacy.h | 1 +
> hw/vfio/container-legacy.c | 38 ++++++++++++++-----------
> hw/vfio/iommufd.c | 15 +---------
> hw/vfio/listener.c | 1 +
> 4 files changed, 25 insertions(+), 30 deletions(-)
>
Applied to vfio-next.
Thanks,
C.
^ permalink raw reply [flat|nested] 6+ messages in thread