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[Qemu-devel] [PATCH v4 26/29] vhost: Huge page align and merge
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH v4 26/29] vhost: Huge page align and merge |
Date: |
Thu, 8 Mar 2018 19:58:08 +0000 |
From: "Dr. David Alan Gilbert" <address@hidden>
Align RAMBlocks to page size alignment, and adjust the merging code
to deal with partial overlap due to that alignment.
This is needed for postcopy so that we can place/fetch whole hugepages
when under userfault.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
hw/virtio/trace-events | 3 ++-
hw/virtio/vhost.c | 66 ++++++++++++++++++++++++++++++++++++++++++--------
2 files changed, 58 insertions(+), 11 deletions(-)
diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 857c495e65..1422ff03ab 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -3,7 +3,8 @@
# hw/virtio/vhost.c
vhost_commit(bool started, bool changed) "Started: %d Changed: %d"
vhost_region_add_section(const char *name, uint64_t gpa, uint64_t size,
uint64_t host) "%s: 0x%"PRIx64"+0x%"PRIx64" @ 0x%"PRIx64
-vhost_region_add_section_abut(const char *name, uint64_t new_size) "%s:
0x%"PRIx64
+vhost_region_add_section_merge(const char *name, uint64_t new_size, uint64_t
gpa, uint64_t owr) "%s: size: 0x%"PRIx64 " gpa: 0x%"PRIx64 " owr: 0x%"PRIx64
+vhost_region_add_section_aligned(const char *name, uint64_t gpa, uint64_t
size, uint64_t host) "%s: 0x%"PRIx64"+0x%"PRIx64" @ 0x%"PRIx64
vhost_section(const char *name, int r) "%s:%d"
# hw/virtio/vhost-user.c
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index d8d0ef92e1..250f886acb 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -522,10 +522,28 @@ static void vhost_region_add_section(struct vhost_dev
*dev,
uint64_t mrs_gpa = section->offset_within_address_space;
uintptr_t mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
section->offset_within_region;
+ RAMBlock *mrs_rb = section->mr->ram_block;
+ size_t mrs_page = qemu_ram_pagesize(mrs_rb);
trace_vhost_region_add_section(section->mr->name, mrs_gpa, mrs_size,
mrs_host);
+ /* Round the section to it's page size */
+ /* First align the start down to a page boundary */
+ uint64_t alignage = mrs_host & (mrs_page - 1);
+ if (alignage) {
+ mrs_host -= alignage;
+ mrs_size += alignage;
+ mrs_gpa -= alignage;
+ }
+ /* Now align the size up to a page boundary */
+ alignage = mrs_size & (mrs_page - 1);
+ if (alignage) {
+ mrs_size += mrs_page - alignage;
+ }
+ trace_vhost_region_add_section_aligned(section->mr->name, mrs_gpa,
mrs_size,
+ mrs_host);
+
if (dev->n_tmp_sections) {
/* Since we already have at least one section, lets see if
* this extends it; since we're scanning in order, we only
@@ -542,18 +560,46 @@ static void vhost_region_add_section(struct vhost_dev
*dev,
prev_sec->offset_within_region;
uint64_t prev_host_end = range_get_last(prev_host_start, prev_size);
- if (prev_gpa_end + 1 == mrs_gpa &&
- prev_host_end + 1 == mrs_host &&
- section->mr == prev_sec->mr &&
- (!dev->vhost_ops->vhost_backend_can_merge ||
- dev->vhost_ops->vhost_backend_can_merge(dev,
+ if (mrs_gpa <= (prev_gpa_end + 1)) {
+ /* OK, looks like overlapping/intersecting - it's possible that
+ * the rounding to page sizes has made them overlap, but they
should
+ * match up in the same RAMBlock if they do.
+ */
+ if (mrs_gpa < prev_gpa_start) {
+ error_report("%s:Section rounded to %"PRIx64
+ " prior to previous %"PRIx64,
+ __func__, mrs_gpa, prev_gpa_start);
+ /* A way to cleanly fail here would be better */
+ return;
+ }
+ /* Offset from the start of the previous GPA to this GPA */
+ size_t offset = mrs_gpa - prev_gpa_start;
+
+ if (prev_host_start + offset == mrs_host &&
+ section->mr == prev_sec->mr &&
+ (!dev->vhost_ops->vhost_backend_can_merge ||
+ dev->vhost_ops->vhost_backend_can_merge(dev,
mrs_host, mrs_size,
prev_host_start, prev_size))) {
- /* The two sections abut */
- need_add = false;
- prev_sec->size = int128_add(prev_sec->size, section->size);
- trace_vhost_region_add_section_abut(section->mr->name,
- mrs_size + prev_size);
+ uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size);
+ need_add = false;
+ prev_sec->offset_within_address_space =
+ MIN(prev_gpa_start, mrs_gpa);
+ prev_sec->offset_within_region =
+ MIN(prev_host_start, mrs_host) -
+ (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr);
+ prev_sec->size = int128_make64(max_end - MIN(prev_host_start,
+ mrs_host));
+ trace_vhost_region_add_section_merge(section->mr->name,
+ int128_get64(prev_sec->size),
+ prev_sec->offset_within_address_space,
+ prev_sec->offset_within_region);
+ } else {
+ error_report("%s: Overlapping but not coherent sections "
+ "at %"PRIx64,
+ __func__, mrs_gpa);
+ return;
+ }
}
}
--
2.14.3
- [Qemu-devel] [PATCH v4 22/29] vhost+postcopy: Call wakeups, (continued)
- [Qemu-devel] [PATCH v4 22/29] vhost+postcopy: Call wakeups, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 21/29] vhost+postcopy: Add vhost waker, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 23/29] libvhost-user: mprotect & madvises for postcopy, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 24/29] vhost-user: Add VHOST_USER_POSTCOPY_END message, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 26/29] vhost: Huge page align and merge,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH v4 29/29] postcopy shared docs, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 25/29] vhost+postcopy: Wire up POSTCOPY_END notify, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 28/29] libvhost-user: Claim support for postcopy, Dr. David Alan Gilbert (git), 2018/03/08
- [Qemu-devel] [PATCH v4 27/29] postcopy: Allow shared memory, Dr. David Alan Gilbert (git), 2018/03/08
- Re: [Qemu-devel] [PATCH v4 00/29] postcopy+vhost-user/shared ram, Dr. David Alan Gilbert, 2018/03/09