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i386 mmu hack: Allow emulate usermode without mmu

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This basicaly mappes virtual addresses to physical addresses 1:1 when
the mmu is disabled in the cpu. So you can use the full 64 bit addressspace
without required to configure the mmu.
This commit is contained in:
Takacs, Philipp 2022-09-29 11:05:25 +02:00
parent 4b327baaf7
commit f2eb1f4711
1 changed files with 6 additions and 6 deletions
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12
qemu/target/i386/excp_helper.c
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@ -635,7 +635,12 @@ do_check_protect_pse36:
/* align to page_size */
pte &= PG_ADDRESS_MASK & ~(page_size - 1);
page_offset = addr & (page_size - 1);
paddr = get_hphys(cs, pte + page_offset, is_write1, &prot);
/* HACK allow full 64 bit mapping in u64 without paging */
if (env->cr[0] & CR0_PG_MASK) {
paddr = get_hphys(cs, pte + page_offset, is_write1, &prot);
} else {
paddr = addr;
}
/* Even if 4MB pages, we map only one 4KB page in the cache to
avoid filling it too fast */
@ -643,11 +648,6 @@ do_check_protect_pse36:
paddr &= TARGET_PAGE_MASK;
assert(prot & (1 << is_write1));
// Unicorn: indentity map guest virtual address to host virtual address
vaddr = addr & TARGET_PAGE_MASK;
paddr = vaddr;
//printf(">>> map address %"PRIx64" to %"PRIx64"\n", vaddr, paddr);
tlb_set_page_with_attrs(cs, vaddr, paddr, cpu_get_mem_attrs(env),
prot, mmu_idx, page_size);
return 0;