From: Raphael Norwitz <raphael.norwitz@nutanix.com>
To: "stefanha@redhat.com" <stefanha@redhat.com>,
"marcandre.lureau@redhat.com" <marcandre.lureau@redhat.com>,
"mst@redhat.com" <mst@redhat.com>,
"david@redhat.com" <david@redhat.com>
Cc: "raphael.s.norwitz@gmail.com" <raphael.s.norwitz@gmail.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Raphael Norwitz <raphael.norwitz@nutanix.com>
Subject: [PATCH v2 3/5] libvhost-user: Simplify VHOST_USER_REM_MEM_REG
Date: Thu, 6 Jan 2022 06:47:33 +0000 [thread overview]
Message-ID: <20220106064717.7477-4-raphael.norwitz@nutanix.com> (raw)
In-Reply-To: <20220106064717.7477-1-raphael.norwitz@nutanix.com>
From: David Hildenbrand <david@redhat.com>
Let's avoid having to manually copy all elements. Copy only the ones
necessary to close the hole and perform the operation in-place without
a second array.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
subprojects/libvhost-user/libvhost-user.c | 30 +++++++++++------------
1 file changed, 14 insertions(+), 16 deletions(-)
diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c
index d61285e991..77ddc96ddf 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -802,10 +802,8 @@ static inline bool reg_equal(VuDevRegion *vudev_reg,
static bool
vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
- int i, j;
- bool found = false;
- VuDevRegion shadow_regions[VHOST_USER_MAX_RAM_SLOTS] = {};
VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m;
+ int i;
if (vmsg->fd_num != 1 ||
vmsg->size != sizeof(vmsg->payload.memreg)) {
@@ -823,28 +821,28 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
DPRINT(" mmap_offset 0x%016"PRIx64"\n",
msg_region->mmap_offset);
- for (i = 0, j = 0; i < dev->nregions; i++) {
- if (!reg_equal(&dev->regions[i], msg_region)) {
- shadow_regions[j].gpa = dev->regions[i].gpa;
- shadow_regions[j].size = dev->regions[i].size;
- shadow_regions[j].qva = dev->regions[i].qva;
- shadow_regions[j].mmap_addr = dev->regions[i].mmap_addr;
- shadow_regions[j].mmap_offset = dev->regions[i].mmap_offset;
- j++;
- } else {
- found = true;
+ for (i = 0; i < dev->nregions; i++) {
+ if (reg_equal(&dev->regions[i], msg_region)) {
VuDevRegion *r = &dev->regions[i];
void *m = (void *) (uintptr_t) r->mmap_addr;
if (m) {
munmap(m, r->size + r->mmap_offset);
}
+
+ break;
}
}
- if (found) {
- memcpy(dev->regions, shadow_regions,
- sizeof(VuDevRegion) * VHOST_USER_MAX_RAM_SLOTS);
+ if (i < dev->nregions) {
+ /*
+ * Shift all affected entries by 1 to close the hole at index i and
+ * zero out the last entry.
+ */
+ memmove(dev->regions + i, dev->regions + i + 1,
+ sizeof(VuDevRegion) * (dev->nregions - i - 1));
+ memset(dev->regions + dev->nregions - 1, 0,
+ sizeof(VuDevRegion));
DPRINT("Successfully removed a region\n");
dev->nregions--;
vmsg_set_reply_u64(vmsg, 0);
--
2.20.1
next prev parent reply other threads:[~2022-01-06 7:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-06 6:47 [PATCH v2 0/5] Clean up error handling in libvhost-user memory mapping Raphael Norwitz
2022-01-06 6:47 ` [PATCH v2 1/5] libvhost-user: Add vu_rem_mem_reg input validation Raphael Norwitz
2022-01-10 8:56 ` David Hildenbrand
2022-01-10 9:36 ` Michael S. Tsirkin
2022-01-10 19:43 ` Raphael Norwitz
2022-01-10 21:11 ` Michael S. Tsirkin
2022-01-11 9:13 ` Stefan Hajnoczi
2022-01-06 6:47 ` [PATCH v2 2/5] libvhost-user: Add vu_add_mem_reg " Raphael Norwitz
2022-01-10 8:56 ` David Hildenbrand
2022-01-06 6:47 ` Raphael Norwitz [this message]
2022-01-06 6:47 ` [PATCH v2 4/5] libvhost-user: prevent over-running max RAM slots Raphael Norwitz
2022-01-10 8:57 ` David Hildenbrand
2022-01-10 9:40 ` Michael S. Tsirkin
2022-01-10 22:38 ` Raphael Norwitz
2022-01-10 11:24 ` Stefan Hajnoczi
2022-01-06 6:47 ` [PATCH v2 5/5] libvhost-user: handle removal of identical regions Raphael Norwitz
2022-01-10 8:58 ` David Hildenbrand
2022-01-10 22:38 ` Raphael Norwitz
2022-01-10 11:25 ` Stefan Hajnoczi
2022-01-10 9:01 ` [PATCH v2 0/5] Clean up error handling in libvhost-user memory mapping David Hildenbrand
2022-01-10 22:36 ` Raphael Norwitz
2022-01-10 11:25 ` Stefan Hajnoczi
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