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[Qemu-devel] [PATCH 2/4] exec: add wrapper for host pointer access
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PATCH 2/4] exec: add wrapper for host pointer access |
Date: |
Wed, 12 Nov 2014 11:44:41 +0200 |
host pointer accesses force pointer math, let's
add a wrapper to make them safer.
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
include/exec/cpu-all.h | 5 +++++
exec.c | 10 +++++-----
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index c085804..9d8d408 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -313,6 +313,11 @@ typedef struct RAMBlock {
int fd;
} RAMBlock;
+static inline void *ramblock_ptr(RAMBlock *block, ram_addr_t offset)
+{
+ return (char *)block->host + offset;
+}
+
typedef struct RAMList {
QemuMutex mutex;
/* Protected by the iothread lock. */
diff --git a/exec.c b/exec.c
index ad5cf12..9648669 100644
--- a/exec.c
+++ b/exec.c
@@ -840,7 +840,7 @@ static void tlb_reset_dirty_range_all(ram_addr_t start,
ram_addr_t length)
block = qemu_get_ram_block(start);
assert(block == qemu_get_ram_block(end - 1));
- start1 = (uintptr_t)block->host + (start - block->offset);
+ start1 = (uintptr_t)ramblock_ptr(block, start - block->offset);
cpu_tlb_reset_dirty_all(start1, length);
}
@@ -1500,7 +1500,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
offset = addr - block->offset;
if (offset < block->length) {
- vaddr = block->host + offset;
+ vaddr = ramblock_ptr(block, offset);
if (block->flags & RAM_PREALLOC) {
;
} else if (xen_enabled()) {
@@ -1551,7 +1551,7 @@ void *qemu_get_ram_block_host_ptr(ram_addr_t addr)
{
RAMBlock *block = qemu_get_ram_block(addr);
- return block->host;
+ return ramblock_ptr(block, 0);
}
/* Return a host pointer to ram allocated with qemu_ram_alloc.
@@ -1578,7 +1578,7 @@ void *qemu_get_ram_ptr(ram_addr_t addr)
xen_map_cache(block->offset, block->length, 1);
}
}
- return block->host + (addr - block->offset);
+ return ramblock_ptr(block, addr - block->offset);
}
/* Return a host pointer to guest's ram. Similar to qemu_get_ram_ptr
@@ -1597,7 +1597,7 @@ static void *qemu_ram_ptr_length(ram_addr_t addr, hwaddr
*size)
if (addr - block->offset < block->length) {
if (addr - block->offset + *size > block->length)
*size = block->length - addr + block->offset;
- return block->host + (addr - block->offset);
+ return ramblock_ptr(block, addr - block->offset);
}
}
--
MST
[Qemu-devel] [PATCH 3/4] cpu: assert host pointer offset within block, Michael S. Tsirkin, 2014/11/12
[Qemu-devel] [PATCH 4/4] cpu: verify that block->host is set, Michael S. Tsirkin, 2014/11/12
Re: [Qemu-devel] [PATCH 0/4] migration: fix CVE-2014-7840, Amit Shah, 2014/11/17