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[Qemu-devel] [PATCH 2/2] Remove guest triggerable abort()


From: Gleb Natapov
Subject: [Qemu-devel] [PATCH 2/2] Remove guest triggerable abort()
Date: Wed, 28 Jul 2010 18:13:23 +0300

This abort() condition is easily triggerable by a guest if it configures
pci bar with unaligned address that overlaps main memory.

Signed-off-by: Gleb Natapov <address@hidden>
---
 kvm-all.c |   16 ++++------------
 1 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index fec6d05..ad46b10 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -437,18 +437,10 @@ static void kvm_set_phys_mem(target_phys_addr_t 
start_addr,
     KVMSlot *mem, old;
     int err;
 
-    if (start_addr & ~TARGET_PAGE_MASK) {
-        if (flags >= IO_MEM_UNASSIGNED) {
-            if (!kvm_lookup_overlapping_slot(s, start_addr,
-                                             start_addr + size)) {
-                return;
-            }
-            fprintf(stderr, "Unaligned split of a KVM memory slot\n");
-        } else {
-            fprintf(stderr, "Only page-aligned memory slots supported\n");
-        }
-        abort();
-    }
+    /* kvm works in page size chunks, but the function may be called
+       with sub-page size and analigned start address. */
+    size = TARGET_PAGE_ALIGN(size);
+    start_addr = TARGET_PAGE_ALIGN(start_addr);
 
     /* KVM does not support read-only slots */
     phys_offset &= ~IO_MEM_ROM;
-- 
1.7.1




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