|
 |
1b1826 |
From daa0c48addc50413b79612d9e7251a9cbf35af48 Mon Sep 17 00:00:00 2001
|
|
|
1b1826 |
From: Alex Williamson <alex.williamson@redhat.com>
|
|
|
1b1826 |
Date: Mon, 20 Nov 2017 16:21:44 +0100
|
|
|
1b1826 |
Subject: [PATCH] vfio/pci: Only mmap >= TARGET_PAGE_SIZE regions
|
|
|
1b1826 |
|
|
|
1b1826 |
RH-Author: Alex Williamson <alex.williamson@redhat.com>
|
|
|
1b1826 |
Message-id: <20171120162044.30263.60064.stgit@gimli.home>
|
|
|
1b1826 |
Patchwork-id: 77755
|
|
|
1b1826 |
O-Subject: [RHEL-7.4.z qemu-kvm PATCH] vfio/pci: Only mmap >= TARGET_PAGE_SIZE regions
|
|
|
1b1826 |
Bugzilla: 1515110
|
|
|
1b1826 |
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
1b1826 |
RH-Acked-by: Thomas Huth <thuth@redhat.com>
|
|
|
1b1826 |
RH-Acked-by: Auger Eric <eric.auger@redhat.com>
|
|
|
1b1826 |
|
|
|
1b1826 |
Upstream Status: RHEL-only (very small subset of db0da029a185)
|
|
|
1b1826 |
Tested: Teradici USB assignment
|
|
|
1b1826 |
|
|
|
1b1826 |
Upstream kernel commit 05f0c03fbac1 ('vfio-pci: Allow to mmap sub-page
|
|
|
1b1826 |
MMIO BARs if the mmio page is exclusive') [RHEL-7.4 390f15a45024] allows
|
|
|
1b1826 |
vfio-pci to expose the VFIO_REGION_INFO_FLAG_MMAP flag, indicating the
|
|
|
1b1826 |
region can be mmap'd, for sub-page PCI BARs iff the BAR is page aligned
|
|
|
1b1826 |
and the remainder of the page can be reserved to ensure that it's not
|
|
|
1b1826 |
used for other purposes. Unfortunately QEMU versions prior to v2.6.0
|
|
|
1b1826 |
blindly accept the MMAP flag with no special handling of these sub-page
|
|
|
1b1826 |
mmaps. This went unnoticed upstream, but was inadvertently fixed by
|
|
|
1b1826 |
commit db0da029a185 ('vfio: Generalize region support') which ensures
|
|
|
1b1826 |
that the region size is a multiple of page size. This returns us to
|
|
|
1b1826 |
the previous behavior where sub-page regions are not mmap'd, even though
|
|
|
1b1826 |
the kernel now allows it. This QEMU commit has since been picked up in
|
|
|
1b1826 |
qemu-kvm with the backport of the above as a33e922436f7. qemu-kvm-rhev
|
|
|
1b1826 |
has had this support since RHEL-7.3. Furthermore, upstream commit
|
|
|
1b1826 |
95251725e335 ('vfio: Add support for mmapping sub-page MMIO BARs')
|
|
|
1b1826 |
allows QEMU to fully make use of these sub-page mmaps. qemu-kvm-rhev
|
|
|
1b1826 |
acquired this capability in the RHEL-7.4 rebase.
|
|
|
1b1826 |
|
|
|
1b1826 |
Here we extract only the portion of db0da029a185 which excludes sub-page
|
|
|
1b1826 |
regions from being mmap'd.
|
|
|
1b1826 |
|
|
|
1b1826 |
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
|
|
|
1b1826 |
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
|
1b1826 |
---
|
|
|
1b1826 |
hw/misc/vfio.c | 3 ++-
|
|
|
1b1826 |
1 file changed, 2 insertions(+), 1 deletion(-)
|
|
|
1b1826 |
|
|
|
1b1826 |
diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
|
|
|
1b1826 |
index 4fdc09a..adfefec 100644
|
|
|
1b1826 |
--- a/hw/misc/vfio.c
|
|
|
1b1826 |
+++ b/hw/misc/vfio.c
|
|
|
1b1826 |
@@ -2576,7 +2576,8 @@ static int vfio_mmap_bar(VFIOBAR *bar, MemoryRegion *mem, MemoryRegion *submem,
|
|
|
1b1826 |
{
|
|
|
1b1826 |
int ret = 0;
|
|
|
1b1826 |
|
|
|
1b1826 |
- if (VFIO_ALLOW_MMAP && size && bar->flags & VFIO_REGION_INFO_FLAG_MMAP) {
|
|
|
1b1826 |
+ if (VFIO_ALLOW_MMAP && size && bar->flags & VFIO_REGION_INFO_FLAG_MMAP &&
|
|
|
1b1826 |
+ !(size & ~TARGET_PAGE_MASK)) {
|
|
|
1b1826 |
int prot = 0;
|
|
|
1b1826 |
|
|
|
1b1826 |
if (bar->flags & VFIO_REGION_INFO_FLAG_READ) {
|
|
|
1b1826 |
--
|
|
|
1b1826 |
1.8.3.1
|
|
|
1b1826 |
|