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Re: [Qemu-devel] [PATCH] fix bits 39:32 of the final physical address wh
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH] fix bits 39:32 of the final physical address when using 4M page |
Date: |
Mon, 07 Jan 2013 14:10:46 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 |
Am 07.01.2013 13:06, schrieb Markus Armbruster:
> Wen Congyang <address@hidden> writes:
>
>> ((pde & 0x1fe000) << 19) is the bits 39:32 of the final physical address, and
>> we shouldn't use unit32_t to calculate it. Convert the type to hwaddr to fix
>> this problem.
>
> Spotted by Coverity.
>
>> Signed-off-by: Wen Congyang <address@hidden>
>>
>> ---
>> target-i386/arch_memory_mapping.c | 11 ++++++++---
>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/target-i386/arch_memory_mapping.c
>> b/target-i386/arch_memory_mapping.c
>> index c6c7874..844893f 100644
>> --- a/target-i386/arch_memory_mapping.c
>> +++ b/target-i386/arch_memory_mapping.c
>> @@ -115,7 +115,7 @@ static void walk_pde2(MemoryMappingList *list,
>> hwaddr pde_start_addr, int32_t a20_mask,
>> bool pse)
>> {
>> - hwaddr pde_addr, pte_start_addr, start_paddr;
>> + hwaddr pde_addr, pte_start_addr, start_paddr, high_paddr;
>> uint32_t pde;
>> target_ulong line_addr, start_vaddr;
>> int i;
>> @@ -130,8 +130,13 @@ static void walk_pde2(MemoryMappingList *list,
>>
>> line_addr = (((unsigned int)i & 0x3ff) << 22);
>> if ((pde & PG_PSE_MASK) && pse) {
>> - /* 4 MB page */
>> - start_paddr = (pde & ~0x3fffff) | ((pde & 0x1fe000) << 19);
>> + /*
>> + * 4 MB page:
>> + * bits 39:32 are bits 20:13 of the PDE
>> + * bit3 31:22 are bits 31:22 of the PDE
>> + */
>> + high_paddr = ((hwaddr)(pde & 0x1fe000) << 19);
>> + start_paddr = (pde & ~0x3fffff) | high_paddr;
>> if (cpu_physical_memory_is_io(start_paddr)) {
>> /* I/O region */
>> continue;
>
> Extra points for extending the comment.
...and a "target-i386: " prefix in the subject would be appreciated,
since it does not seem to fix a general issue.
Andreas
>
> Reviewed-by: Markus Armbruster <address@hidden>
>
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