[Qemu-devel] [PULL 0/1] xen-140130

[Qemu-devel] [PULL 0/1] xen-140130

[Stefano Stabellini]

The following changes since commit 0169c511554cb0014a00290b0d3d26c31a49818f:

  Merge remote-tracking branch 'qemu-kvm/uq/master' into staging (2014-01-24 15:52:44 -0800)

are available in the git repository at:


  git://xenbits.xen.org/people/sstabellini/qemu-dm.git xen-140130

for you to fetch changes up to 360e607b88a23d378f6efaa769c76d26f538234d:

  address_space_translate: do not cross page boundaries (2014-01-30 14:20:45 +0000)

----------------------------------------------------------------
Stefano Stabellini (1):
      address_space_translate: do not cross page boundaries

 exec.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

[Qemu-devel] [PULL 1/1] address_space_translate: do not cross page boundaries

[Stefano Stabellini]

From: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>

The following commit:

commit 149f54b53b7666a3facd45e86eece60ce7d3b114
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Fri May 24 12:59:37 2013 +0200

    memory: add address_space_translate

breaks Xen support in QEMU, in particular the Xen mapcache. The effect
is that one Windows XP installation out of ten would end up with BSOD.

The reason is that after this commit l in address_space_rw can span a
page boundary, however qemu_get_ram_ptr still calls xen_map_cache asking
to map a single page (if block->offset == 0).

Fix the issue by reverting to the previous behaviour: do not return a
length from address_space_translate_internal that can span a page
boundary.

Also in address_space_translate do not ignore the length returned by
address_space_translate_internal.

This patch should be backported to QEMU 1.6.x.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Anthony Perard <anthony.perard@citrix.com>
Tested-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-stable@nongnu.org
---
 exec.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/exec.c b/exec.c
index 2435d9e..9ad0a4b 100644
--- a/exec.c
+++ b/exec.c
@@ -325,7 +325,7 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
                                  hwaddr *plen, bool resolve_subpage)
 {
     MemoryRegionSection *section;
-    Int128 diff;
+    Int128 diff, diff_page;
 
     section = address_space_lookup_region(d, addr, resolve_subpage);
     /* Compute offset within MemoryRegionSection */
@@ -334,7 +334,9 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
     /* Compute offset within MemoryRegion */
     *xlat = addr + section->offset_within_region;
 
+    diff_page = int128_make64(((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr);
     diff = int128_sub(section->mr->size, int128_make64(addr));
+    diff = int128_min(diff, diff_page);
     *plen = int128_get64(int128_min(diff, int128_make64(*plen)));
     return section;
 }
@@ -349,7 +351,7 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
     hwaddr len = *plen;
 
     for (;;) {
-        section = address_space_translate_internal(as->dispatch, addr, &addr, plen, true);
+        section = address_space_translate_internal(as->dispatch, addr, &addr, &len, true);
         mr = section->mr;
 
         if (!mr->iommu_ops) {
-- 
1.7.10.4

Re: [Qemu-devel] [PULL 0/1] xen-140130

[Stefano Stabellini]

Anthony,
I would appreciate if you could pull this branch quickly, as I am
looking forward to backport the patch to the qemu-xen tree for the Xen
4.4 release.
Thanks,

Stefano

On Thu, 30 Jan 2014, Stefano Stabellini wrote:
> The following changes since commit 0169c511554cb0014a00290b0d3d26c31a49818f:
> 
>   Merge remote-tracking branch 'qemu-kvm/uq/master' into staging (2014-01-24 15:52:44 -0800)
> 
> are available in the git repository at:
> 
> 
>   git://xenbits.xen.org/people/sstabellini/qemu-dm.git xen-140130
> 
> for you to fetch changes up to 360e607b88a23d378f6efaa769c76d26f538234d:
> 
>   address_space_translate: do not cross page boundaries (2014-01-30 14:20:45 +0000)
> 
> ----------------------------------------------------------------
> Stefano Stabellini (1):
>       address_space_translate: do not cross page boundaries
> 
>  exec.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 

Re: [Qemu-devel] [PULL 0/1] xen-140130

[Peter Maydell]

On 30 January 2014 14:24, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> The following changes since commit 0169c511554cb0014a00290b0d3d26c31a49818f:
>
>   Merge remote-tracking branch 'qemu-kvm/uq/master' into staging (2014-01-24 15:52:44 -0800)
>
> are available in the git repository at:
>
>
>   git://xenbits.xen.org/people/sstabellini/qemu-dm.git xen-140130
>
> for you to fetch changes up to 360e607b88a23d378f6efaa769c76d26f538234d:
>
>   address_space_translate: do not cross page boundaries (2014-01-30 14:20:45 +0000)
>
> ----------------------------------------------------------------
> Stefano Stabellini (1):
>       address_space_translate: do not cross page boundaries
>
>  exec.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Applied, thanks.

-- PMM