File 0238-exec-do-not-clamp-accesses-to-MMIO-.patch of Package qemu.5921

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File 0238-exec-do-not-clamp-accesses-to-MMIO-.patch of Package qemu.5921

From c8eb48b60882615cf800cdffdc34b9c792665862 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 17 Jun 2015 10:40:27 +0200
Subject: [PATCH] exec: do not clamp accesses to MMIO regions
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It is common for MMIO registers to overlap, for example a 4 byte register
at 0xcf8 (totally random choice... :)) and a 1 byte register at 0xcf9.
If these registers are implemented via separate MemoryRegions, it is
wrong to clamp the accesses as the value written would be truncated.

Hence for these regions the effects of commit 23820db (exec: Respect
as_translate_internal length clamp, 2015-03-16, previously applied as
commit c3c1bb99) must be skipped.

Tested-by: Hervé Poussineau <hpoussin@reactos.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 965eb2fcdfe919ecced6c34803535ad32dc1249c)
[BR: support patch for BSC#969122]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 exec.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/exec.c b/exec.c
index a58be1a9ff..b740901a02 100644
--- a/exec.c
+++ b/exec.c
@@ -325,6 +325,7 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
                                  hwaddr *plen, bool resolve_subpage)
 {
     MemoryRegionSection *section;
+    MemoryRegion *mr;
     Int128 diff;
 
     section = address_space_lookup_region(d, addr, resolve_subpage);
@@ -334,8 +335,11 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
     /* Compute offset within MemoryRegion */
     *xlat = addr + section->offset_within_region;
 
-    diff = int128_sub(section->mr->size, int128_make64(addr));
-    *plen = int128_get64(int128_min(diff, int128_make64(*plen)));
+    mr = section->mr;
+    if (memory_region_is_ram(mr)) {
+        diff = int128_sub(mr->size, int128_make64(addr));
+        *plen = int128_get64(int128_min(diff, int128_make64(*plen)));
+    }
     return section;
 }

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File 0238-exec-do-not-clamp-accesses-to-MMIO-.patch of Package qemu.5921

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