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plugins: force slow path when plugins instrument memory ops

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The lack of SVE memory instrumentation has been an omission in plugin
handling since it was introduced. Fortunately we can utilise the
probe_* functions to force all all memory access to follow the slow
path. We do this by checking the access type and presence of plugin
memory callbacks and if set return the TLB_MMIO flag.

We have to jump through a few hoops in user mode to re-use the flag
but it was the desired effect:

 ./qemu-system-aarch64 -display none -serial mon:stdio \
   -M virt -cpu max -semihosting-config enable=on \
   -kernel ./tests/tcg/aarch64-softmmu/memory-sve \
   -plugin ./contrib/plugins/libexeclog.so,ifilter=st1w,afilter=0x40001808 -d plugin

gives (disas doesn't currently understand st1w):

  0, 0x40001808, 0xe54342a0, ".byte 0xa0, 0x42, 0x43, 0xe5", store, 0x40213010, RAM, store, 0x40213014, RAM, store, 0x40213018, RAM

And for user-mode:

  ./qemu-aarch64 \
    -plugin contrib/plugins/libexeclog.so,afilter=0x4007c0 \
    -d plugin \
    ./tests/tcg/aarch64-linux-user/sha512-sve

gives:

  1..10
  ok 1 - do_test(&tests[i])
  0, 0x4007c0, 0xa4004b80, ".byte 0x80, 0x4b, 0x00, 0xa4", load, 0x5500800370, load, 0x5500800371, load, 0x5500800372, load, 0x5500800373, load, 0x5500800374, load, 0x5500800375, load, 0x5500800376, load, 0x5500800377, load, 0x5500800378, load, 0x5500800379, load, 0x550080037a, load, 0x550080037b, load, 0x550080037c, load, 0x550080037d, load, 0x550080037e, load, 0x550080037f, load, 0x5500800380, load, 0x5500800381, load, 0x5500800382, load, 0x5500800383, load, 0x5500800384, load, 0x5500800385, load, 0x5500800386, lo
  ad, 0x5500800387, load, 0x5500800388, load, 0x5500800389, load, 0x550080038a, load, 0x550080038b, load, 0x550080038c, load, 0x550080038d, load, 0x550080038e, load, 0x550080038f, load, 0x5500800390, load, 0x5500800391, load, 0x5500800392, load, 0x5500800393, load, 0x5500800394, load, 0x5500800395, load, 0x5500800396, load, 0x5500800397, load, 0x5500800398, load, 0x5500800399, load, 0x550080039a, load, 0x550080039b, load, 0x550080039c, load, 0x550080039d, load, 0x550080039e, load, 0x550080039f, load, 0x55008003a0, load, 0x55008003a1, load, 0x55008003a2, load, 0x55008003a3, load, 0x55008003a4, load, 0x55008003a5, load, 0x55008003a6, load, 0x55008003a7, load, 0x55008003a8, load, 0x55008003a9, load, 0x55008003aa, load, 0x55008003ab, load, 0x55008003ac, load, 0x55008003ad, load, 0x55008003ae, load, 0x55008003af

(4007c0 is the ld1b in the sha512-sve)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Cc: Robert Henry <robhenry@microsoft.com>
Cc: Aaron Lindsay <aaron@os.amperecomputing.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230630180423.558337-20-alex.bennee@linaro.org>
This commit is contained in:
Alex Bennée 2023-06-30 19:04:04 +01:00
parent 465af4db96
commit 6d03226b42
8 changed files with 96 additions and 21 deletions
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17
include/hw/core/cpu.h
View file

@ -976,6 +976,23 @@ void cpu_watchpoint_remove_by_ref(CPUState *cpu, CPUWatchpoint *watchpoint);
void cpu_watchpoint_remove_all(CPUState *cpu, int mask);
#endif
/**
* cpu_plugin_mem_cbs_enabled() - are plugin memory callbacks enabled?
* @cs: CPUState pointer
*
* The memory callbacks are installed if a plugin has instrumented an
* instruction for memory. This can be useful to know if you want to
* force a slow path for a series of memory accesses.
*/
static inline bool cpu_plugin_mem_cbs_enabled(const CPUState *cpu)
{
#ifdef CONFIG_PLUGIN
return !!cpu->plugin_mem_cbs;
#else
return false;
#endif
}
/**
* cpu_get_address_space:
* @cpu: CPU to get address space from