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* [PATCH 00/33] linux-user: Improve host and guest page size handling
@ 2023-08-18 17:11 Richard Henderson
  2023-08-18 17:11 ` [PATCH 01/33] accel/tcg: Remove qemu_host_page_size from page_protect/page_unprotect Richard Henderson
                   ` (32 more replies)
  0 siblings, 33 replies; 44+ messages in thread
From: Richard Henderson @ 2023-08-18 17:11 UTC (permalink / raw)
  To: qemu-devel

While working on mmap issues for 8.1, I noticed a lot of corner
cases of host != guest page size that we implement poorly.
This seems to be particularly visible on Apple M1 with 16k pages,
more so than Power with 64k pages for some reason.

Objective 1 is to deprecate and (essentially) disable the -p option.

The effect of -p is apparently confusing, so much so that our own
testsuite misuses it.  One cannot really change the host page size,
and pretending otherwise means that we don't treat the host memory
system correctly, and stuff breaks.

I have not yet done the same work for bsd-user.

Objective 2 is to allow the guest page size to change to match the host.

There are corner cases of host != guest page size will fail in odd ways.
For case of host > guest page size, the issues could be solved with
softmmu, allowing a non-linear mapping between host and guest addresses
and also disconnecting host and guest page permissions.

However, host < guest page has issues with SIGBUS which I believe to be
totally unfixable.  At minimum one would need to monitor changes to all
files mapped in the address space, but I'm sure there is much more.

But as always the best behaviour is obtained when the host and guest
page sizes match -- there are no corner cases to contend with.

There are a set of guests which can be configured to use multiple page
sizes, and therefore software developed for those guests (usually) does
not hard-code a particular page size.  For those, we can allow the
page size to vary and let the guest match the host.

I have only changed aarch64, alpha and ppc guests so far, as those
are both easy to test and, especially for the case of alpha's default
8k page size, prone to failure.


r~


PS: There are probably minor conflicts without
Based-on: 20230816180338.572576-1-richard.henderson@linaro.org
("[PATCH v4 00/18] linux-user: Implement VDSOs")

Richard Henderson (33):
  accel/tcg: Remove qemu_host_page_size from page_protect/page_unprotect
  linux-user: Adjust SVr4 NULL page mapping
  linux-user: Remove qemu_host_page_{size,mask} in probe_guest_base
  linux-user: Remove qemu_host_page_size from create_elf_tables
  linux-user/hppa: Simplify init_guest_commpage
  linux-user/nios2: Remove qemu_host_page_size from init_guest_commpage
  linux-user/arm: Remove qemu_host_page_size from init_guest_commpage
  linux-user: Remove qemu_host_page_{size,mask} from mmap.c
  linux-user: Remove REAL_HOST_PAGE_ALIGN from mmap.c
  linux-user: Remove HOST_PAGE_ALIGN from mmap.c
  migration: Remove qemu_host_page_size
  hw/tpm: Remove HOST_PAGE_ALIGN from tpm_ppi_init
  softmmu/physmem: Remove qemu_host_page_size
  softmmu/physmem: Remove HOST_PAGE_ALIGN
  linux-user: Remove qemu_host_page_size from main
  linux-user: Split out target_mmap__locked
  linux-user: Move some mmap checks outside the lock
  linux-user: Fix sub-host-page mmap
  linux-user: Split out mmap_end
  linux-user: Do early mmap placement only for reserved_va
  linux-user: Split out mmap_h_eq_g
  linux-user: Split out mmap_h_lt_g
  linux-user: Split out mmap_h_gt_g
  tests/tcg: Remove run-test-mmap-*
  tests/tcg: Extend file in linux-madvise.c
  linux-user: Deprecate and disable -p pagesize
  cpu: Remove page_size_init
  accel/tcg: Disconnect TargetPageDataNode from page size
  linux-user: Allow TARGET_PAGE_BITS_VARY
  target/arm: Enable TARGET_PAGE_BITS_VARY for AArch64 user-only
  linux-user: Bound mmap_min_addr by host page size
  target/ppc: Enable TARGET_PAGE_BITS_VARY for user-only
  target/alpha: Enable TARGET_PAGE_BITS_VARY for user-only

 bsd-user/qemu.h                           |   7 +
 include/exec/cpu-common.h                 |   7 -
 include/hw/core/cpu.h                     |   2 -
 target/alpha/cpu-param.h                  |  16 +-
 target/arm/cpu-param.h                    |   6 +-
 target/ppc/cpu-param.h                    |   9 +-
 accel/tcg/translate-all.c                 |   1 -
 accel/tcg/user-exec.c                     |  31 +-
 bsd-user/main.c                           |  12 +
 cpu.c                                     |  13 -
 hw/tpm/tpm_ppi.c                          |   3 +-
 linux-user/elfload.c                      |  67 +-
 linux-user/main.c                         |  33 +-
 linux-user/mmap.c                         | 714 +++++++++++++---------
 migration/ram.c                           |  22 +-
 softmmu/physmem.c                         |  17 +-
 softmmu/vl.c                              |   1 -
 target/arm/cpu.c                          |  51 +-
 tests/tcg/multiarch/linux/linux-madvise.c |   2 +
 tests/tcg/alpha/Makefile.target           |   3 -
 tests/tcg/arm/Makefile.target             |   3 -
 tests/tcg/hppa/Makefile.target            |   3 -
 tests/tcg/i386/Makefile.target            |   3 -
 tests/tcg/m68k/Makefile.target            |   3 -
 tests/tcg/multiarch/Makefile.target       |   9 -
 tests/tcg/ppc/Makefile.target             |  12 -
 tests/tcg/sh4/Makefile.target             |   3 -
 tests/tcg/sparc64/Makefile.target         |   6 -
 28 files changed, 614 insertions(+), 445 deletions(-)
 delete mode 100644 tests/tcg/ppc/Makefile.target
 delete mode 100644 tests/tcg/sparc64/Makefile.target

-- 
2.34.1



^ permalink raw reply	[flat|nested] 44+ messages in thread

end of thread, other threads:[~2023-08-21  7:08 UTC | newest]

Thread overview: 44+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-08-18 17:11 [PATCH 00/33] linux-user: Improve host and guest page size handling Richard Henderson
2023-08-18 17:11 ` [PATCH 01/33] accel/tcg: Remove qemu_host_page_size from page_protect/page_unprotect Richard Henderson
2023-08-18 17:11 ` [PATCH 02/33] linux-user: Adjust SVr4 NULL page mapping Richard Henderson
2023-08-18 17:11 ` [PATCH 03/33] linux-user: Remove qemu_host_page_{size, mask} in probe_guest_base Richard Henderson
2023-08-18 17:11 ` [PATCH 04/33] linux-user: Remove qemu_host_page_size from create_elf_tables Richard Henderson
2023-08-18 17:11 ` [PATCH 05/33] linux-user/hppa: Simplify init_guest_commpage Richard Henderson
2023-08-18 17:12 ` [PATCH 06/33] linux-user/nios2: Remove qemu_host_page_size from init_guest_commpage Richard Henderson
2023-08-18 17:12 ` [PATCH 07/33] linux-user/arm: " Richard Henderson
2023-08-18 17:12 ` [PATCH 08/33] linux-user: Remove qemu_host_page_{size, mask} from mmap.c Richard Henderson
2023-08-18 17:12 ` [PATCH 09/33] linux-user: Remove REAL_HOST_PAGE_ALIGN " Richard Henderson
2023-08-21  7:08   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 10/33] linux-user: Remove HOST_PAGE_ALIGN " Richard Henderson
2023-08-18 17:12 ` [PATCH 11/33] migration: Remove qemu_host_page_size Richard Henderson
2023-08-18 17:12 ` [PATCH 12/33] hw/tpm: Remove HOST_PAGE_ALIGN from tpm_ppi_init Richard Henderson
2023-08-18 17:12 ` [PATCH 13/33] softmmu/physmem: Remove qemu_host_page_size Richard Henderson
2023-08-18 17:12 ` [PATCH 14/33] softmmu/physmem: Remove HOST_PAGE_ALIGN Richard Henderson
2023-08-18 17:12 ` [PATCH 15/33] linux-user: Remove qemu_host_page_size from main Richard Henderson
2023-08-18 17:12 ` [PATCH 16/33] linux-user: Split out target_mmap__locked Richard Henderson
2023-08-21  6:43   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 17/33] linux-user: Move some mmap checks outside the lock Richard Henderson
2023-08-21  6:47   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 18/33] linux-user: Fix sub-host-page mmap Richard Henderson
2023-08-18 17:12 ` [PATCH 19/33] linux-user: Split out mmap_end Richard Henderson
2023-08-21  6:49   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 20/33] linux-user: Do early mmap placement only for reserved_va Richard Henderson
2023-08-18 17:12 ` [PATCH 21/33] linux-user: Split out mmap_h_eq_g Richard Henderson
2023-08-18 17:12 ` [PATCH 22/33] linux-user: Split out mmap_h_lt_g Richard Henderson
2023-08-18 17:12 ` [PATCH 23/33] linux-user: Split out mmap_h_gt_g Richard Henderson
2023-08-18 17:12 ` [PATCH 24/33] tests/tcg: Remove run-test-mmap-* Richard Henderson
2023-08-18 17:12 ` [PATCH 25/33] tests/tcg: Extend file in linux-madvise.c Richard Henderson
2023-08-21  6:54   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 26/33] linux-user: Deprecate and disable -p pagesize Richard Henderson
2023-08-21  6:58   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 27/33] cpu: Remove page_size_init Richard Henderson
2023-08-21  7:00   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 28/33] accel/tcg: Disconnect TargetPageDataNode from page size Richard Henderson
2023-08-21  7:03   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 29/33] linux-user: Allow TARGET_PAGE_BITS_VARY Richard Henderson
2023-08-18 17:12 ` [PATCH 30/33] target/arm: Enable TARGET_PAGE_BITS_VARY for AArch64 user-only Richard Henderson
2023-08-21  7:05   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 31/33] linux-user: Bound mmap_min_addr by host page size Richard Henderson
2023-08-18 17:12 ` [PATCH 32/33] target/ppc: Enable TARGET_PAGE_BITS_VARY for user-only Richard Henderson
2023-08-21  7:06   ` Philippe Mathieu-Daudé
2023-08-18 17:12 ` [PATCH 33/33] target/alpha: " Richard Henderson

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