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[PATCH v4 06/10] Refactor out libvhost-user fault generation logic
From: |
Raphael Norwitz |
Subject: |
[PATCH v4 06/10] Refactor out libvhost-user fault generation logic |
Date: |
Thu, 21 May 2020 05:00:47 +0000 (UTC) |
In libvhost-user, the incoming postcopy migration path for setting the
backend's memory tables has become convolued. In particular, moving the
logic which starts generating faults, having received the final ACK from
qemu can be moved to a separate function. This simplifies the code
substantially.
This logic will also be needed by the postcopy path once the
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS feature is supported.
Signed-off-by: Raphael Norwitz <address@hidden>
---
contrib/libvhost-user/libvhost-user.c | 147 ++++++++++++++++++----------------
1 file changed, 79 insertions(+), 68 deletions(-)
diff --git a/contrib/libvhost-user/libvhost-user.c
b/contrib/libvhost-user/libvhost-user.c
index 3bca996..cccfa22 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -584,6 +584,84 @@ map_ring(VuDev *dev, VuVirtq *vq)
}
static bool
+generate_faults(VuDev *dev) {
+ int i;
+ for (i = 0; i < dev->nregions; i++) {
+ VuDevRegion *dev_region = &dev->regions[i];
+ int ret;
+#ifdef UFFDIO_REGISTER
+ /*
+ * We should already have an open ufd. Mark each memory
+ * range as ufd.
+ * Discard any mapping we have here; note I can't use MADV_REMOVE
+ * or fallocate to make the hole since I don't want to lose
+ * data that's already arrived in the shared process.
+ * TODO: How to do hugepage
+ */
+ ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
+ dev_region->size + dev_region->mmap_offset,
+ MADV_DONTNEED);
+ if (ret) {
+ fprintf(stderr,
+ "%s: Failed to madvise(DONTNEED) region %d: %s\n",
+ __func__, i, strerror(errno));
+ }
+ /*
+ * Turn off transparent hugepages so we dont get lose wakeups
+ * in neighbouring pages.
+ * TODO: Turn this backon later.
+ */
+ ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
+ dev_region->size + dev_region->mmap_offset,
+ MADV_NOHUGEPAGE);
+ if (ret) {
+ /*
+ * Note: This can happen legally on kernels that are configured
+ * without madvise'able hugepages
+ */
+ fprintf(stderr,
+ "%s: Failed to madvise(NOHUGEPAGE) region %d: %s\n",
+ __func__, i, strerror(errno));
+ }
+ struct uffdio_register reg_struct;
+ reg_struct.range.start = (uintptr_t)dev_region->mmap_addr;
+ reg_struct.range.len = dev_region->size + dev_region->mmap_offset;
+ reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
+
+ if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER, ®_struct)) {
+ vu_panic(dev, "%s: Failed to userfault region %d "
+ "@%p + size:%zx offset: %zx: (ufd=%d)%s\n",
+ __func__, i,
+ dev_region->mmap_addr,
+ dev_region->size, dev_region->mmap_offset,
+ dev->postcopy_ufd, strerror(errno));
+ return false;
+ }
+ if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) {
+ vu_panic(dev, "%s Region (%d) doesn't support COPY",
+ __func__, i);
+ return false;
+ }
+ DPRINT("%s: region %d: Registered userfault for %"
+ PRIx64 " + %" PRIx64 "\n", __func__, i,
+ (uint64_t)reg_struct.range.start,
+ (uint64_t)reg_struct.range.len);
+ /* Now it's registered we can let the client at it */
+ if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
+ dev_region->size + dev_region->mmap_offset,
+ PROT_READ | PROT_WRITE)) {
+ vu_panic(dev, "failed to mprotect region %d for postcopy (%s)",
+ i, strerror(errno));
+ return false;
+ }
+ /* TODO: Stash 'zero' support flags somewhere */
+#endif
+ }
+
+ return true;
+}
+
+static bool
vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
{
int i;
@@ -655,74 +733,7 @@ vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg
*vmsg)
}
/* OK, now we can go and register the memory and generate faults */
- for (i = 0; i < dev->nregions; i++) {
- VuDevRegion *dev_region = &dev->regions[i];
- int ret;
-#ifdef UFFDIO_REGISTER
- /* We should already have an open ufd. Mark each memory
- * range as ufd.
- * Discard any mapping we have here; note I can't use MADV_REMOVE
- * or fallocate to make the hole since I don't want to lose
- * data that's already arrived in the shared process.
- * TODO: How to do hugepage
- */
- ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
- dev_region->size + dev_region->mmap_offset,
- MADV_DONTNEED);
- if (ret) {
- fprintf(stderr,
- "%s: Failed to madvise(DONTNEED) region %d: %s\n",
- __func__, i, strerror(errno));
- }
- /* Turn off transparent hugepages so we dont get lose wakeups
- * in neighbouring pages.
- * TODO: Turn this backon later.
- */
- ret = madvise((void *)(uintptr_t)dev_region->mmap_addr,
- dev_region->size + dev_region->mmap_offset,
- MADV_NOHUGEPAGE);
- if (ret) {
- /* Note: This can happen legally on kernels that are configured
- * without madvise'able hugepages
- */
- fprintf(stderr,
- "%s: Failed to madvise(NOHUGEPAGE) region %d: %s\n",
- __func__, i, strerror(errno));
- }
- struct uffdio_register reg_struct;
- reg_struct.range.start = (uintptr_t)dev_region->mmap_addr;
- reg_struct.range.len = dev_region->size + dev_region->mmap_offset;
- reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
-
- if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER, ®_struct)) {
- vu_panic(dev, "%s: Failed to userfault region %d "
- "@%p + size:%zx offset: %zx: (ufd=%d)%s\n",
- __func__, i,
- dev_region->mmap_addr,
- dev_region->size, dev_region->mmap_offset,
- dev->postcopy_ufd, strerror(errno));
- return false;
- }
- if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) {
- vu_panic(dev, "%s Region (%d) doesn't support COPY",
- __func__, i);
- return false;
- }
- DPRINT("%s: region %d: Registered userfault for %"
- PRIx64 " + %" PRIx64 "\n", __func__, i,
- (uint64_t)reg_struct.range.start,
- (uint64_t)reg_struct.range.len);
- /* Now it's registered we can let the client at it */
- if (mprotect((void *)(uintptr_t)dev_region->mmap_addr,
- dev_region->size + dev_region->mmap_offset,
- PROT_READ | PROT_WRITE)) {
- vu_panic(dev, "failed to mprotect region %d for postcopy (%s)",
- i, strerror(errno));
- return false;
- }
- /* TODO: Stash 'zero' support flags somewhere */
-#endif
- }
+ (void)generate_faults(dev);
return false;
}
--
1.8.3.1
- [PATCH v4 00/10] vhost-user: Lift Max Ram Slots Limitation, Raphael Norwitz, 2020/05/21
- [PATCH v4 01/10] Add helper to populate vhost-user message regions, Raphael Norwitz, 2020/05/21
- [PATCH v4 02/10] Add vhost-user helper to get MemoryRegion data, Raphael Norwitz, 2020/05/21
- [PATCH v4 03/10] Add VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS, Raphael Norwitz, 2020/05/21
- [PATCH v4 04/10] Transmit vhost-user memory regions individually, Raphael Norwitz, 2020/05/21
- [PATCH v4 05/10] Lift max memory slots limit imposed by vhost-user, Raphael Norwitz, 2020/05/21
- [PATCH v4 06/10] Refactor out libvhost-user fault generation logic,
Raphael Norwitz <=
- [PATCH v4 07/10] Support ram slot configuration in libvhost-user, Raphael Norwitz, 2020/05/21
- [PATCH v4 08/10] Support adding individual regions in libvhost-user, Raphael Norwitz, 2020/05/21
- [PATCH v4 09/10] Support individual region unmap in libvhost-user, Raphael Norwitz, 2020/05/21
- [PATCH v4 10/10] Lift max ram slots limit in libvhost-user, Raphael Norwitz, 2020/05/21