* [Qemu-devel] [PATCH] exec: Respect as_tranlsate_internal length clamp
@ 2015-03-17 5:35 Peter Crosthwaite
2015-03-18 11:11 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Peter Crosthwaite @ 2015-03-17 5:35 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, Peter Crosthwaite
address_space_translate_internal will clamp the *plen length argument
based on the size of the memory region being queried. The iommu walker
logic in addresss_space_translate was ignoring this by discarding the
post fn call value of *plen. Fix by just always using *plen as the
length argument throughout the fn, removing the len local variable.
This fixes a bootloader bug when a single elf section spans multiple
QEMU memory regions.
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
---
exec.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/exec.c b/exec.c
index e97071a..8b922db 100644
--- a/exec.c
+++ b/exec.c
@@ -380,7 +380,6 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
IOMMUTLBEntry iotlb;
MemoryRegionSection *section;
MemoryRegion *mr;
- hwaddr len = *plen;
rcu_read_lock();
for (;;) {
@@ -395,7 +394,7 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
iotlb = mr->iommu_ops->translate(mr, addr, is_write);
addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
| (addr & iotlb.addr_mask));
- len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
+ *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
if (!(iotlb.perm & (1 << is_write))) {
mr = &io_mem_unassigned;
break;
@@ -406,10 +405,9 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
if (xen_enabled() && memory_access_is_direct(mr, is_write)) {
hwaddr page = ((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr;
- len = MIN(page, len);
+ *plen = MIN(page, *plen);
}
- *plen = len;
*xlat = addr;
rcu_read_unlock();
return mr;
--
2.3.1.2.g90df61e.dirty
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH] exec: Respect as_tranlsate_internal length clamp
2015-03-17 5:35 [Qemu-devel] [PATCH] exec: Respect as_tranlsate_internal length clamp Peter Crosthwaite
@ 2015-03-18 11:11 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2015-03-18 11:11 UTC (permalink / raw)
To: Peter Crosthwaite, qemu-devel
On 17/03/2015 06:35, Peter Crosthwaite wrote:
> address_space_translate_internal will clamp the *plen length argument
> based on the size of the memory region being queried. The iommu walker
> logic in addresss_space_translate was ignoring this by discarding the
> post fn call value of *plen. Fix by just always using *plen as the
> length argument throughout the fn, removing the len local variable.
>
> This fixes a bootloader bug when a single elf section spans multiple
> QEMU memory regions.
>
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> ---
> exec.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index e97071a..8b922db 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -380,7 +380,6 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
> IOMMUTLBEntry iotlb;
> MemoryRegionSection *section;
> MemoryRegion *mr;
> - hwaddr len = *plen;
>
> rcu_read_lock();
> for (;;) {
> @@ -395,7 +394,7 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
> iotlb = mr->iommu_ops->translate(mr, addr, is_write);
> addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
> | (addr & iotlb.addr_mask));
> - len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
> + *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
> if (!(iotlb.perm & (1 << is_write))) {
> mr = &io_mem_unassigned;
> break;
> @@ -406,10 +405,9 @@ MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
>
> if (xen_enabled() && memory_access_is_direct(mr, is_write)) {
> hwaddr page = ((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr;
> - len = MIN(page, len);
> + *plen = MIN(page, *plen);
> }
>
> - *plen = len;
> *xlat = addr;
> rcu_read_unlock();
> return mr;
>
Applied, thanks.
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-03-17 5:35 [Qemu-devel] [PATCH] exec: Respect as_tranlsate_internal length clamp Peter Crosthwaite
2015-03-18 11:11 ` Paolo Bonzini
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