Re: [PATCH 2/3] vdpa: Add vhost_vdpa_section_end
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-10-05 08:19:11
Also in:
qemu-devel
On Tue, Oct 05, 2021 at 10:01:30AM +0200, Eugenio Pérez wrote:
Abstract this operation, that will be reused when validating the region against the iova range that the device supports. Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Note that as defined end is actually 1 byte beyond end of section. As such it can e.g. overflow if cast to u64. So be careful to use int128 ops with it. Also - document?
quoted hunk
--- hw/virtio/vhost-vdpa.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index ea1aa71ad8..a1de6c7c9c 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c@@ -24,6 +24,15 @@ #include "trace.h" #include "qemu-common.h" +static Int128 vhost_vdpa_section_end(const MemoryRegionSection *section) +{ + Int128 llend = int128_make64(section->offset_within_address_space); + llend = int128_add(llend, section->size); + llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK)); + + return llend; +} + static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section) { return (!memory_region_is_ram(section->mr) &&@@ -160,10 +169,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, } iova = TARGET_PAGE_ALIGN(section->offset_within_address_space); - llend = int128_make64(section->offset_within_address_space); - llend = int128_add(llend, section->size); - llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK)); - + llend = vhost_vdpa_section_end(section); if (int128_ge(int128_make64(iova), llend)) { return; }@@ -221,9 +227,7 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, } iova = TARGET_PAGE_ALIGN(section->offset_within_address_space); - llend = int128_make64(section->offset_within_address_space); - llend = int128_add(llend, section->size); - llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK)); + llend = vhost_vdpa_section_end(section); trace_vhost_vdpa_listener_region_del(v, iova, int128_get64(llend));-- 2.27.0
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