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target-i386: fix abort on bad PML4E/PDPTE/PDE/PTE addresses

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The code used to walk IA-32e page-tables, and possibly PAE page-tables,
uses the bit mask ~0xfff to get the next PML4E/PDPTE/PDE/PTE address.

However, as we use a uint64_t to store the resulting address, that mask
gets expanded to 0xfffffffffffff000 which not only ends up selecting
reserved bits but also selects the XD bit (execute-disable) which
happens to be enabled by Windows 8, causing qemu_get_ram_ptr() to abort.

This commit fixes that problem by replacing ~0xfff by a correct mask
that only selects the address bit range (ie. bits 51:12).

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Luiz Capitulino 2013-05-28 14:19:22 -04:00
parent a678e26cbe
commit fbc2ed9518
1 changed files with 6 additions and 4 deletions
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10
target-i386/arch_memory_mapping.c
View file

@ -75,6 +75,8 @@ static void walk_pte2(MemoryMappingList *list,
}
/* PAE Paging or IA-32e Paging */
#define PLM4_ADDR_MASK 0xffffffffff000 /* selects bits 51:12 */
static void walk_pde(MemoryMappingList *list, hwaddr pde_start_addr,
int32_t a20_mask, target_ulong start_line_addr)
{
@ -105,7 +107,7 @@ static void walk_pde(MemoryMappingList *list, hwaddr pde_start_addr,
continue;
}
pte_start_addr = (pde & ~0xfff) & a20_mask;
pte_start_addr = (pde & PLM4_ADDR_MASK) & a20_mask;
walk_pte(list, pte_start_addr, a20_mask, line_addr);
}
}
@ -208,7 +210,7 @@ static void walk_pdpe(MemoryMappingList *list,
continue;
}
pde_start_addr = (pdpe & ~0xfff) & a20_mask;
pde_start_addr = (pdpe & PLM4_ADDR_MASK) & a20_mask;
walk_pde(list, pde_start_addr, a20_mask, line_addr);
}
}
@ -231,7 +233,7 @@ static void walk_pml4e(MemoryMappingList *list,
}
line_addr = ((i & 0x1ffULL) << 39) | (0xffffULL << 48);
pdpe_start_addr = (pml4e & ~0xfff) & a20_mask;
pdpe_start_addr = (pml4e & PLM4_ADDR_MASK) & a20_mask;
walk_pdpe(list, pdpe_start_addr, a20_mask, line_addr);
}
}
@ -249,7 +251,7 @@ int cpu_get_memory_mapping(MemoryMappingList *list, CPUArchState *env)
if (env->hflags & HF_LMA_MASK) {
hwaddr pml4e_addr;
pml4e_addr = (env->cr[3] & ~0xfff) & env->a20_mask;
pml4e_addr = (env->cr[3] & PLM4_ADDR_MASK) & env->a20_mask;
walk_pml4e(list, pml4e_addr, env->a20_mask);
} else
#endif