Commit Graph

43 Commits

Author SHA1 Message Date
Thomas Huth
2068cabd3f Do not include cpu.h if it's not really necessary
Stop including cpu.h in files that don't need it.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210416171314.2074665-4-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-02 17:24:51 +02:00
Richard Henderson
46b12f461c exec: Rename guest_{addr,range}_valid to *_untagged
The places that use these are better off using untagged
addresses, so do not provide a tagged versions.  Rename
to make it clear about the address type.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210212184902.1251044-16-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-02-16 11:04:53 +00:00
Richard Henderson
3e8f1628e8 exec: Use cpu_untagged_addr in g2h; split out g2h_untagged
Use g2h_untagged in contexts that have no cpu, e.g. the binary
loaders that operate before the primary cpu is created.  As a
colollary, target_mmap and friends must use untagged addresses,
since they are used by the loaders.

Use g2h_untagged on values returned from target_mmap, as the
kernel never applies a tag itself.

Use g2h_untagged on all pc values.  The only current user of
tags, aarch64, removes tags from code addresses upon branch,
so "pc" is always untagged.

Use g2h with the cpu context on hand wherever possible.

Use g2h_untagged in lock_user, which will be updated soon.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210212184902.1251044-13-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2021-02-16 11:04:53 +00:00
Claudio Fontana
7827168471 cpu: tcg_ops: move to tcg-cpu-ops.h, keep a pointer in CPUClass
we cannot in principle make the TCG Operations field definitions
conditional on CONFIG_TCG in code that is included by both common_ss
and specific_ss modules.

Therefore, what we can do safely to restrict the TCG fields to TCG-only
builds, is to move all tcg cpu operations into a separate header file,
which is only included by TCG, target-specific code.

This leaves just a NULL pointer in the cpu.h for the non-TCG builds.

This also tidies up the code in all targets a bit, having all TCG cpu
operations neatly contained by a dedicated data struct.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210204163931.7358-16-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-02-05 10:24:15 -10:00
Claudio Fontana
c73bdb35a9 cpu: move debug_check_watchpoint to tcg_ops
commit 568496c0c0 ("cpu: Add callback to check architectural") and
commit 3826121d92 ("target-arm: Implement checking of fired")
introduced an ARM-specific hack for cpu_check_watchpoint.

Make debug_check_watchpoint optional, and move it to tcg_ops.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210204163931.7358-15-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-02-05 10:24:14 -10:00
Eduardo Habkost
e124536f37 cpu: Move tlb_fill to tcg_ops
[claudio: wrapped target code in CONFIG_TCG]

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210204163931.7358-7-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-02-05 10:24:14 -10:00
Paolo Bonzini
3b9bd3f46b remove TCG includes from common code
Enable removing tcg/$tcg_arch from the include path when TCG is disabled.
Move translate-all.h to include/exec, since stubs exist for the functions
defined therein.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-02 21:03:36 +01:00
Chen Qun
f190bf05f8 accel/tcg/user-exec: silence the compiler warnings
When using -Wimplicit-fallthrough in our CFLAGS, the compiler showed warning:
../accel/tcg/user-exec.c: In function ‘handle_cpu_signal’:
../accel/tcg/user-exec.c:169:13: warning: this statement may fall through [-Wimplicit-fallthrough=]
  169 |             cpu_exit_tb_from_sighandler(cpu, old_set);
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../accel/tcg/user-exec.c:172:9: note: here
  172 |         default:

Mark the cpu_exit_tb_from_sighandler() function with QEMU_NORETURN to fix it.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20201211152426.350966-8-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-12-18 09:14:23 +01:00
Kele Huang
62475e9d00 accel/tcg: Fix computing of is_write for MIPS
Detect all MIPS store instructions in cpu_signal_handler for all available
MIPS versions, and set is_write if encountering such store instructions.

This fixed the error while dealing with self-modified code for MIPS.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Kele Huang <kele.hwang@gmail.com>
Signed-off-by: Xu Zou <iwatchnima@gmail.com>
Message-Id: <20201002081420.10814-1-kele.hwang@gmail.com>
[rth: Use uintptr_t for pc to fix n32 build error.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-10-08 05:57:32 -05:00
zhaolichang
e3a6e0daf4 qemu/: fix some comment spelling errors
I found that there are many spelling errors in the comments of qemu,
so I used the spellcheck tool to check the spelling errors
and finally found some spelling errors in the folder.

Signed-off-by: zhaolichang <zhaolichang@huawei.com>
Reviewed-by: Alex Bennee <alex.bennee@linaro.org>
Message-Id: <20200917075029.313-2-zhaolichang@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-09-17 20:35:43 +02:00
Paolo Bonzini
139c1837db meson: rename included C source files to .c.inc
With Makefiles that have automatically generated dependencies, you
generated includes are set as dependencies of the Makefile, so that they
are built before everything else and they are available when first
building the .c files.

Alternatively you can use a fine-grained dependency, e.g.

        target/arm/translate.o: target/arm/decode-neon-shared.inc.c

With Meson you have only one choice and it is a third option, namely
"build at the beginning of the corresponding target"; the way you
express it is to list the includes in the sources of that target.

The problem is that Meson decides if something is a source vs. a
generated include by looking at the extension: '.c', '.cc', '.m', '.C'
are sources, while everything else is considered an include---including
'.inc.c'.

Use '.c.inc' to avoid this, as it is consistent with our other convention
of using '.rst.inc' for included reStructuredText files.  The editorconfig
file is adjusted.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-08-21 06:18:30 -04:00
Paolo Bonzini
243af0225a trace: switch position of headers to what Meson requires
Meson doesn't enjoy the same flexibility we have with Make in choosing
the include path.  In particular the tracing headers are using
$(build_root)/$(<D).

In order to keep the include directives unchanged,
the simplest solution is to generate headers with patterns like
"trace/trace-audio.h" and place forwarding headers in the source tree
such that for example "audio/trace.h" includes "trace/trace-audio.h".

This patch is too ugly to be applied to the Makefiles now.  It's only
a way to separate the changes to the tracing header files from the
Meson rewrite of the tracing logic.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-08-21 06:18:24 -04:00
Nick Hudson
71b04329c4 accel/tcg: Provide a NetBSD specific aarch64 cpu_signal_handler
Fix qemu build on NetBSD/evbarm-aarch64 by providing a NetBSD specific
cpu_signal_handler.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Nick Hudson <skrll@netbsd.org>
Message-Id: <20200517101529.5367-1-skrll@netbsd.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-06-02 08:42:37 -07:00
Nick Hudson
853d9a4be8 accel/tcg: Adjust cpu_signal_handler for NetBSD/arm
Fix building on NetBSD/arm by extracting the FSR value from the
correct siginfo_t field.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Nick Hudson <skrll@netbsd.org>
Message-Id: <20200516154147.24842-1-skrll@netbsd.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-06-02 08:42:37 -07:00
Richard Henderson
b9e60257c1 accel/tcg: Add endian-specific cpu_{ld, st}* operations
We currently have target-endian versions of these operations,
but no easy way to force a specific endianness.  This can be
helpful if the target has endian-specific operations, or a mode
that swaps endianness.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200508154359.7494-7-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-05-11 11:22:06 +01:00
Richard Henderson
069cfe77d6 accel/tcg: Add probe_access_flags
This new interface will allow targets to probe for a page
and then handle watchpoints themselves.  This will be most
useful for vector predicated memory operations, where one
page lookup can be used for many operations, and one test
can avoid many watchpoint checks.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200508154359.7494-6-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-05-11 11:21:34 +01:00
Richard Henderson
7a1bfee682 accel/tcg: Adjust probe_access call to page_check_range
We have validated that addr+size does not cross a page boundary.
Therefore we need to validate exactly one page.  We can achieve
that passing any value 1 <= x <= size to page_check_range.

Passing 1 will simplify the next patch.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200508154359.7494-5-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2020-05-11 11:14:02 +01:00
Philippe Mathieu-Daudé
dcb32f1d8f tcg: Search includes from the project root source directory
We currently search both the root and the tcg/ directories for tcg
files:

  $ git grep '#include "tcg/' | wc -l
  28

  $ git grep '#include "tcg[^/]' | wc -l
  94

To simplify the preprocessor search path, unify by expliciting the
tcg/ directory.

Patch created mechanically by running:

  $ for x in \
      tcg.h tcg-mo.h tcg-op.h tcg-opc.h \
      tcg-op-gvec.h tcg-gvec-desc.h; do \
    sed -i "s,#include \"$x\",#include \"tcg/$x\"," \
      $(git grep -l "#include \"$x\""); \
    done

Acked-by: David Gibson <david@gibson.dropbear.id.au> (ppc parts)
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200101112303.20724-2-philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-01-15 15:13:10 -10:00
Richard Henderson
ed4cfbcd50 cputlb: Expand cpu_ldst_useronly_template.h in user-exec.c
With the tracing hooks, the inline functions are no longer
so simple.  Reduce the amount of preprocessor obfuscation
by expanding the text of each of the functions generated.

Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-01-15 15:13:10 -10:00
Emilio G. Cota
cfec388518 atomic_template: add inline trace/plugin helpers
In preparation for plugin support.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2019-10-28 15:12:38 +00:00
Alex Bennée
504f73f7b3 trace: add mmu_index to mem_info
We are going to re-use mem_info later for plugins and will need to
track the mmu_idx for softmmu code.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
2019-10-28 15:12:38 +00:00
David Hildenbrand
c25c283df0 tcg: Factor out probe_write() logic into probe_access()
Let's also allow to probe other access types.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190830100959.26615-3-david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-09-03 08:34:18 -07:00
David Hildenbrand
fef39ccd56 tcg: Make probe_write() return a pointer to the host page
... similar to tlb_vaddr_to_host(); however, allow access to the host
page except when TLB_NOTDIRTY or TLB_MMIO is set.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190830100959.26615-2-david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-09-03 08:34:18 -07:00
David Hildenbrand
ca86cf328c tcg: Enforce single page access in probe_write()
Let's enforce the interface restriction.

Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190826075112.25637-5-david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-09-03 08:34:18 -07:00
David Hildenbrand
59e96ac6cb tcg: Factor out CONFIG_USER_ONLY probe_write() from s390x code
Factor it out into common code. Similar to the !CONFIG_USER_ONLY variant,
let's not allow to cross page boundaries.

Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190826075112.25637-4-david@redhat.com>
[rth: Move cpu & cc variables inside if block.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-09-03 08:34:18 -07:00
Richard Henderson
52ba13f042 tcg: Release mmap_lock on translation fault
Turn helper_retaddr into a multi-state flag that may now also
indicate when we're performing a read on behalf of the translator.
In this case, release the mmap_lock before the longjmp back to
the main cpu loop, and thereby avoid a failing assert therein.

Fixes: https://bugs.launchpad.net/qemu/+bug/1832353
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-07-14 12:19:01 +02:00
Richard Henderson
08b97f7ff2 tcg: Introduce set/clear_helper_retaddr
At present we have a potential error in that helper_retaddr contains
data for handle_cpu_signal, but we have not ensured that those stores
will be scheduled properly before the operation that may fault.

It might be that these races are not in practice observable, due to
our use of -fno-strict-aliasing, but better safe than sorry.

Adjust all of the setters of helper_retaddr.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-07-14 12:19:00 +02:00
Richard Henderson
29a0af618d cpu: Replace ENV_GET_CPU with env_cpu
Now that we have both ArchCPU and CPUArchState, we can define
this generically instead of via macro in each target's cpu.h.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-06-10 07:03:34 -07:00
Richard Henderson
69963f5709 tcg: Remove CPUClass::handle_mmu_fault
This hook is now completely replaced by tlb_fill.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-05-10 11:12:50 -07:00
Richard Henderson
da6bbf8513 tcg: Add CPUClass::tlb_fill
This hook will replace the (user-only mode specific) handle_mmu_fault
hook, and the (system mode specific) tlb_fill function.

The handle_mmu_fault hook was written as if there was a valid
way to recover from an mmu fault, and had 3 possible return states.
In reality, the only valid action is to raise an exception,
return to the main loop, and deliver the SIGSEGV to the guest.

Note that all of the current implementations of handle_mmu_fault
for guests which support linux-user do in fact only ever return 1,
which is the signal to return to the main loop.

Using the hook for system mode requires that all targets be converted,
so for now the hook is (optionally) used only from user-only mode.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-05-10 07:55:06 -07:00
Thomas Huth
fb0343d5b4 tcg: Fix LGPL version number
It's either "GNU *Library* General Public version 2" or "GNU Lesser
General Public version *2.1*", but there was no "version 2.0" of the
"Lesser" library. So assume that version 2.1 is meant here.

Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <1548252536-6242-5-git-send-email-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2019-01-30 11:01:52 +01:00
Peter Maydell
f454a54f3b accel/tcg/user-exec: Don't parse aarch64 insns to test for read vs write
In cpu_signal_handler() for aarch64 hosts, currently we parse
the faulting instruction to see if it is a load or a store.
Since the 3.16 kernel (~2014), the kernel has provided us with
the syndrome register for a fault, which includes the WnR bit.
Use this instead if it is present, only falling back to
instruction parsing if not.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190108180014.32386-1-peter.maydell@linaro.org
2019-01-29 11:46:04 +00:00
Alistair Francis
464e447a0c tcg: Add RISC-V cpu signal handler
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <c445175310fa836b61fd862a55628907f0093194.1545246859.git.alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-12-26 06:40:02 +11:00
Richard Henderson
e6cd4bb59b tcg: Split CONFIG_ATOMIC128
GCC7+ will no longer advertise support for 16-byte __atomic operations
if only cmpxchg is supported, as for x86_64.  Fortunately, x86_64 still
has support for __sync_compare_and_swap_16 and we can make use of that.
AArch64 does not have, nor ever has had such support, so open-code it.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18 19:46:36 -07:00
Pavel Dovgalyuk
afd46fcad2 icount: fix cpu_restore_state_from_tb for non-tb-exit cases
In icount mode, instructions that access io memory spaces in the middle
of the translation block invoke TB recompilation.  After recompilation,
such instructions become last in the TB and are allowed to access io
memory spaces.

When the code includes instruction like i386 'xchg eax, 0xffffd080'
which accesses APIC, QEMU goes into an infinite loop of the recompilation.

This instruction includes two memory accesses - one read and one write.
After the first access, APIC calls cpu_report_tpr_access, which restores
the CPU state to get the current eip.  But cpu_restore_state_from_tb
resets the cpu->can_do_io flag which makes the second memory access invalid.
Therefore the second memory access causes a recompilation of the block.
Then these operations repeat again and again.

This patch moves resetting cpu->can_do_io flag from
cpu_restore_state_from_tb to cpu_loop_exit* functions.

It also adds a parameter for cpu_restore_state which controls restoring
icount.  There is no need to restore icount when we only query CPU state
without breaking the TB.  Restoring it in such cases leads to the
incorrect flow of the virtual time.

In most cases new parameter is true (icount should be recalculated).
But there are two cases in i386 and openrisc when the CPU state is only
queried without the need to break the TB.  This patch fixes both of
these cases.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Message-Id: <20180409091320.12504.35329.stgit@pasha-VirtualBox>
[rth: Make can_do_io setting unconditional; move from cpu_exec;
make cpu_loop_exit_{noexc,restore} call cpu_loop_exit.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-04-11 09:05:22 +10:00
Peter Maydell
b1cef6d02f Drop remaining bits of ia64 host support
We dropped support for ia64 host CPUs in the 2.11 release (removing
the TCG backend for it, and advertising the support as being
completely removed in the changelog).  However there are a few bits
and pieces of code still floating about.  Remove those, too.

We can drop the check in configure for "ia64 or hppa host?"
entirely, because we don't support hppa hosts either any more.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1516897189-11035-1-git-send-email-peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-02-05 18:09:45 +01:00
Laurent Vivier
98670d47cd accel/tcg: add size paremeter in tlb_fill()
The MC68040 MMU provides the size of the access that
triggers the page fault.

This size is set in the Special Status Word which
is written in the stack frame of the access fault
exception.

So we need the size in m68k_cpu_unassigned_access() and
m68k_cpu_handle_mmu_fault().

To be able to do that, this patch modifies the prototype of
handle_mmu_fault handler, tlb_fill() and probe_write().
do_unassigned_access() already includes a size parameter.

This patch also updates handle_mmu_fault handlers and
tlb_fill() of all targets (only parameter, no code change).

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20180118193846.24953-2-laurent@vivier.eu>
2018-01-25 16:02:24 +01:00
Peter Maydell
9c4bbee9e3 page_unprotect(): handle calls to pages that are PAGE_WRITE
If multiple guest threads in user-mode emulation write to a
page which QEMU has marked read-only because of cached TCG
translations, the threads can race in page_unprotect:

 * threads A & B both try to do a write to a page with code in it at
   the same time (ie which we've made non-writeable, so SEGV)
 * they race into the signal handler with this faulting address
 * thread A happens to get to page_unprotect() first and takes the
   mmap lock, so thread B sits waiting for it to be done
 * A then finds the page, marks it PAGE_WRITE and mprotect()s it writable
 * A can then continue OK (returns from signal handler to retry the
   memory access)
 * ...but when B gets the mmap lock it finds that the page is already
   PAGE_WRITE, and so it exits page_unprotect() via the "not due to
   protected translation" code path, and wrongly delivers the signal
   to the guest rather than just retrying the access

In particular, this meant that trying to run 'javac' in user-mode
emulation would fail with a spurious guest SIGSEGV.

Handle this by making page_unprotect() assume that a call for a page
which is already PAGE_WRITE is due to a race of this sort and return
a "fault handled" indication.

Since this would cause an infinite loop if we ever called
page_unprotect() for some other kind of fault than "write failed due
to bad access permissions", tighten the condition in
handle_cpu_signal() to check the signal number and si_code, and add a
comment so that if somebody does ever find themselves debugging an
infinite loop of faults they have some clue about why.

(The trick for identifying the correct setting for
current_tb_invalidated for thread B (needed to handle the precise-SMC
case) is due to Richard Henderson.  Paolo Bonzini suggested just
relying on si_code rather than trying anything more complicated.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1511879725-9576-3-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-01-23 14:20:53 +01:00
Peter Maydell
a78b1299f1 linux-user: Propagate siginfo_t through to handle_cpu_signal()
Currently all the architecture/OS specific cpu_signal_handler()
functions call handle_cpu_signal() without passing it the
siginfo_t. We're going to want that so we can look at the si_code
to determine whether this is a SEGV_ACCERR access violation or
some other kind of fault, so change the functions to pass through
the pointer to the siginfo_t rather than just the si_addr value.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <1511879725-9576-2-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2018-01-23 14:20:52 +01:00
Peter Maydell
34d49937e4 accel/tcg: Handle atomic accesses to notdirty memory correctly
To do a write to memory that is marked as notdirty, we need
to invalidate any TBs we have cached for that memory, and
update the cpu physical memory dirty flags for VGA and migration.
The slowpath code in notdirty_mem_write() does all this correctly,
but the new atomic handling code in atomic_mmu_lookup() doesn't
do anything at all, it just clears the dirty bit in the TLB.

The effect of this bug is that if the first write to a notdirty
page for which we have cached TBs is by a guest atomic access,
we fail to invalidate the TBs and subsequently will execute
incorrect code. This can be seen by trying to run 'javac' on AArch64.

Use the new notdirty_call_before() and notdirty_call_after()
functions to correctly handle the update to notdirty memory
in the atomic codepath.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1511201308-23580-3-git-send-email-peter.maydell@linaro.org
2017-11-21 12:09:25 +00:00
Richard Henderson
ec603b5584 tcg: Record code_gen_buffer address for user-only memory helpers
When we handle a signal from a fault within a user-only memory helper,
we cannot cpu_restore_state with the PC found within the signal frame.
Use a TLS variable, helper_retaddr, to record the unwind start point
to find the faulting guest insn.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-11-15 10:33:27 +01:00
Philippe Mathieu-Daudé
a411d29637 accel/tcg: move USER code to user-exec.c
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20170912211934.20919-1-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17 06:52:19 -07:00
Philippe Mathieu-Daudé
5841066668 accel/tcg: move user-exec to accel/tcg/
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20170911213328.9701-3-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17 06:52:19 -07:00