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[Qemu-devel] [PULL 23/33] vhost: Simplify ring verification checks
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PULL 23/33] vhost: Simplify ring verification checks |
Date: |
Tue, 16 Jan 2018 06:48:07 +0200 |
From: "Dr. David Alan Gilbert" <address@hidden>
vhost_verify_ring_mappings() were used to verify that
rings are still accessible and related memory hasn't
been moved after flatview is updated.
It was doing checks by mapping ring's GPA+len and
checking that HVA hadn't changed with new memory map.
To avoid maybe expensive mapping call, we were
identifying address range that changed and were doing
mapping only if ring was in changed range.
However it's not neccessary to perform ring's GPA
mapping as we already have its current HVA and all
we need is to verify that ring's GPA translates to
the same HVA in updated flatview.
This will allow the following patches to simplify the range
comparison that was previously needed to avoid expensive
verify_ring_mapping calls.
Signed-off-by: Igor Mammedov <address@hidden>
with modifications by:
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
Reviewed-by: Igor Mammedov <address@hidden>
---
hw/virtio/vhost.c | 79 +++++++++++++++++++++++++++++--------------------------
1 file changed, 42 insertions(+), 37 deletions(-)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 83df043..0bdd833 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -450,35 +450,37 @@ static void vhost_memory_unmap(struct vhost_dev *dev,
void *buffer,
}
}
-static int vhost_verify_ring_part_mapping(struct vhost_dev *dev,
- void *part,
- uint64_t part_addr,
- uint64_t part_size,
- uint64_t start_addr,
- uint64_t size)
-{
- hwaddr l;
- void *p;
- int r = 0;
-
- if (!ranges_overlap(start_addr, size, part_addr, part_size)) {
+static int vhost_verify_ring_part_mapping(void *ring_hva,
+ uint64_t ring_gpa,
+ uint64_t ring_size,
+ void *reg_hva,
+ uint64_t reg_gpa,
+ uint64_t reg_size)
+{
+ uint64_t hva_ring_offset;
+ uint64_t ring_last = range_get_last(ring_gpa, ring_size);
+ uint64_t reg_last = range_get_last(reg_gpa, reg_size);
+
+ if (ring_last < reg_gpa || ring_gpa > reg_last) {
return 0;
}
- l = part_size;
- p = vhost_memory_map(dev, part_addr, &l, 1);
- if (!p || l != part_size) {
- r = -ENOMEM;
+ /* check that whole ring's is mapped */
+ if (ring_last > reg_last) {
+ return -ENOMEM;
}
- if (p != part) {
- r = -EBUSY;
+ /* check that ring's MemoryRegion wasn't replaced */
+ hva_ring_offset = ring_gpa - reg_gpa;
+ if (ring_hva != reg_hva + hva_ring_offset) {
+ return -EBUSY;
}
- vhost_memory_unmap(dev, p, l, 0, 0);
- return r;
+
+ return 0;
}
static int vhost_verify_ring_mappings(struct vhost_dev *dev,
- uint64_t start_addr,
- uint64_t size)
+ void *reg_hva,
+ uint64_t reg_gpa,
+ uint64_t reg_size)
{
int i, j;
int r = 0;
@@ -492,22 +494,25 @@ static int vhost_verify_ring_mappings(struct vhost_dev
*dev,
struct vhost_virtqueue *vq = dev->vqs + i;
j = 0;
- r = vhost_verify_ring_part_mapping(dev, vq->desc, vq->desc_phys,
- vq->desc_size, start_addr, size);
+ r = vhost_verify_ring_part_mapping(
+ vq->desc, vq->desc_phys, vq->desc_size,
+ reg_hva, reg_gpa, reg_size);
if (r) {
break;
}
j++;
- r = vhost_verify_ring_part_mapping(dev, vq->avail, vq->avail_phys,
- vq->avail_size, start_addr, size);
+ r = vhost_verify_ring_part_mapping(
+ vq->desc, vq->desc_phys, vq->desc_size,
+ reg_hva, reg_gpa, reg_size);
if (r) {
break;
}
j++;
- r = vhost_verify_ring_part_mapping(dev, vq->used, vq->used_phys,
- vq->used_size, start_addr, size);
+ r = vhost_verify_ring_part_mapping(
+ vq->desc, vq->desc_phys, vq->desc_size,
+ reg_hva, reg_gpa, reg_size);
if (r) {
break;
}
@@ -635,13 +640,11 @@ static void vhost_commit(MemoryListener *listener)
{
struct vhost_dev *dev = container_of(listener, struct vhost_dev,
memory_listener);
- hwaddr start_addr = 0;
- ram_addr_t size = 0;
MemoryRegionSection *old_sections;
int n_old_sections;
-
uint64_t log_size;
int r;
+ int i;
old_sections = dev->mem_sections;
n_old_sections = dev->n_mem_sections;
@@ -658,12 +661,14 @@ static void vhost_commit(MemoryListener *listener)
goto out;
}
- if (dev->started) {
- start_addr = dev->mem_changed_start_addr;
- size = dev->mem_changed_end_addr - dev->mem_changed_start_addr + 1;
-
- r = vhost_verify_ring_mappings(dev, start_addr, size);
- assert(r >= 0);
+ for (i = 0; i < dev->mem->nregions; i++) {
+ if (vhost_verify_ring_mappings(dev,
+ (void *)dev->mem->regions[i].userspace_addr,
+ dev->mem->regions[i].guest_phys_addr,
+ dev->mem->regions[i].memory_size)) {
+ error_report("Verify ring failure on region %d", i);
+ abort();
+ }
}
if (!dev->log_enabled) {
--
MST
- [Qemu-devel] [PULL 13/33] hw/pci-bridge: fix QEMU crash because of pcie-root-port, (continued)
- [Qemu-devel] [PULL 13/33] hw/pci-bridge: fix QEMU crash because of pcie-root-port, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 15/33] hw/acpi-build: Make next_base easy to follow, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 16/33] vhost-user-test: fix features mask, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 17/33] vhost-user-test: extract read-guest-mem test from main loop, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 18/33] vhost-user-test: setup virtqueues in all tests, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 19/33] vhost-user-test: make features mask an init_virtio_dev() argument, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 20/33] vhost-user-test: use init_virtio_dev in multiqueue test, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 21/33] vhost: Build temporary section list and deref after commit, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 22/33] vhost: Move log_dirty check, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 24/33] vhost: Merge sections added to temporary list, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 23/33] vhost: Simplify ring verification checks,
Michael S. Tsirkin <=
- [Qemu-devel] [PULL 26/33] x86_iommu: check if machine has PCI bus, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 28/33] tests: acpi: init table descriptor in test_dst_table(), Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 29/33] tests: acpi: rename test_acpi_tables()/test_dst_table() to reflect its usage, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 27/33] tests: acpi: move tested tables array allocation outside of test_acpi_dsdt_table(), Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 30/33] tests: acpi: add comments to fetch_rsdt_referenced_tables/data->tables usage, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 25/33] x86_iommu: Move machine check to x86_iommu_realize(), Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 31/33] vhost-user: factor out msg head and payload, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 32/33] vhost-user: fix misaligned access to payload, Michael S. Tsirkin, 2018/01/15
- [Qemu-devel] [PULL 33/33] vhost: remove assertion to prevent crash, Michael S. Tsirkin, 2018/01/15
- Re: [Qemu-devel] [PULL 00/33] pc, pci, virtio: features, fixes, cleanups, Peter Maydell, 2018/01/16