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Re: [Qemu-devel] [PATCH 0/6] Multi-level page tables and userland mappin
From: |
Paul Brook |
Subject: |
Re: [Qemu-devel] [PATCH 0/6] Multi-level page tables and userland mapping fixes. |
Date: |
Sun, 28 Feb 2010 23:23:53 +0000 |
User-agent: |
KMail/1.12.4 (Linux/2.6.32-trunk-amd64; KDE/4.3.4; x86_64; ; ) |
> Which brings us to the problem of exec.c and the address spaces therein.
> First, there was the fact that TARGET_PHYS_ADDR_SPACE_BITS was constrained
> to be no larger than 32 (with a partial hack for Alpha to extend this to
> 42 bits). Second, that this physical address space value was applied to
> virtual addresses via page_find.
On further investigation (I missed this the first time round) it gets worse
than that :-( While userspace emulation uses PageDesc to describe virtual
pages, system emulation uses it to track physical pages. This probably helps
explain why the existing code is so confused.
I'm not sure why we have separate l1_map and l1_phys_map. My guess is it's an
attempt to save memory, on the theory that typically only a small faction of
ram will be used to hold code.
> This patch series untangles this somewhat.
Looks like a fairly good start, however they're missing a Signed-off-by.
Paul
- [Qemu-devel] [PATCH 5/6] linux-user: Use h2g_valid in qemu_vmalloc., (continued)
- [Qemu-devel] [PATCH 5/6] linux-user: Use h2g_valid in qemu_vmalloc., Richard Henderson, 2010/02/11
- [Qemu-devel] [PATCH 0/7] Multi-level page tables and userland mapping fixes, v2, Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 1/7] Move TARGET_PHYS_ADDR_SPACE_BITS to target-*/cpu.h., Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 3/7] Fix last page errors in page_set_flags and page_check_range., Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 7/7] Assert arguments in range for guest address space., Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 5/7] linux-user: Use h2g_valid in qemu_vmalloc., Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 2/7] Use TARGET_VIRT_ADDR_SPACE_BITS in h2g_valid., Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 6/7] linux-user: Fix mmap_find_vma returning invalid addresses., Richard Henderson, 2010/02/15
- [Qemu-devel] [PATCH 4/7] Implement multi-level page tables., Richard Henderson, 2010/02/15
- Re: [Qemu-devel] [PATCH 0/6] Multi-level page tables and userland mapping fixes.,
Paul Brook <=