Peter Maydell <[email protected]> writes:
> On Wed, 18 Sept 2024 at 22:08, Alex Bennée <[email protected]> wrote:
>>
>> The following changes since commit 2b81c046252fbfb375ad30632362fc16e6e22bd5:
>>
>> Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu into
>> staging (2024-09-17 14:02:18 +0100)
>>
>> are available in the Git repository at:
>>
>> https://gitlab.com/stsquad/qemu.git tags/pull-tcg-plugin-memory-180924-2
>>
>> for you to fetch changes up to a33f4871e0a0f4bf1cb037ab29fae7df7f2fc658:
>>
>> contrib/plugins: avoid hanging program (2024-09-18 21:02:36 +0100)
>>
>> ----------------------------------------------------------------
>> TCG plugin memory instrumentation updates
>>
>> - deprecate plugins on 32 bit hosts
>> - deprecate plugins with TCI
>> - extend memory API to save value
>> - add check-tcg tests to exercise new memory API
>> - fix timer deadlock with non-changing timer
>> - add basic block vector plugin to contrib
>> - add cflow plugin to contrib
>> - extend syscall plugin to dump write memory
>> - validate ips plugin arguments meet minimum slice value
>>
>> ----------------------------------------------------------------
>
> Fails to build on macos:
> https://gitlab.com/qemu-project/qemu/-/jobs/7865151156
>
> ../tests/tcg/plugins/mem.c:12:10: fatal error: 'endian.h' file not found
>
> endian.h is a Linuxism.
Doh - I'd written it off the failure as waiting for the MacOS bump and
didn't see the actual error. I'll see what we can do.
>
> While I'm looking at the code, this caught my eye:
>
> case QEMU_PLUGIN_MEM_VALUE_U64:
> {
> uint64_t *p = (uint64_t *) &ri->data[offset];
> uint64_t val = be ? htobe64(value.data.u64) : htole64(value.data.u64);
> if (is_store) {
> *p = val;
> } else if (*p != val) {
> unseen_data = true;
> }
> break;
> }
>
> Casting a random byte pointer to uint64_t* like that
> and dereferencing it isn't valid -- it can fault if
> it's not aligned correctly.
Hmm in the normal case of x86 hosts we will never hit this. I guess we
could do a memcpy step and then the byteswap?
> I suspect the plugin needs to define versions of at least some
> of the functionality in qemu's include/qemu/bswap.h.
Could it be included directly without bringing in the rest of QEMU's
include deps?
>
> thanks
> -- PMM
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
