Le 29/02/2020 à 01:43, Lirong Yuan a écrit :
> On Fri, Feb 21, 2020 at 5:09 PM Lirong Yuan <yua...@google.com> wrote:
>>
>> This change allows us to set custom base address for guest programs. It is
>> needed to allow qemu to work with Thread Sanitizer (TSan), which has
>> specific boundary definitions for memory mappings on different platforms:
>> https://github.com/llvm/llvm-project/blob/master/compiler-rt/lib/tsan/rtl/tsan_platform.h
Could you give more details and some examples?
Thanks,
Laurent
>> Signed-off-by: Lirong Yuan <yua...@google.com>
>> ---
>> linux-user/main.c | 12 ++++++++++++
>> linux-user/mmap.c | 3 ++-
>> linux-user/qemu.h | 5 +++++
>> 3 files changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/linux-user/main.c b/linux-user/main.c
>> index fba833aac9..c01af6bfee 100644
>> --- a/linux-user/main.c
>> +++ b/linux-user/main.c
>> @@ -336,6 +336,16 @@ static void handle_arg_guest_base(const char *arg)
>> have_guest_base = 1;
>> }
>>
>> +static void handle_arg_mmap_base(const char *arg)
>> +{
>> + int err = qemu_strtoul(arg, NULL, 0, &mmap_base);
>> + if (err) {
>> + fprintf(stderr, "Invalid mmap_base: %s, err: %d\n", arg, err);
>> + exit(EXIT_FAILURE);
>> + }
>> + mmap_next_start = mmap_base;
>> +}
>> +
>> static void handle_arg_reserved_va(const char *arg)
>> {
>> char *p;
>> @@ -440,6 +450,8 @@ static const struct qemu_argument arg_table[] = {
>> "uname", "set qemu uname release string to 'uname'"},
>> {"B", "QEMU_GUEST_BASE", true, handle_arg_guest_base,
>> "address", "set guest_base address to 'address'"},
>> + {"mmap_base", "QEMU_MMAP_BASE", true, handle_arg_mmap_base,
>> + "", "begin allocating guest pages at this host address"},
>> {"R", "QEMU_RESERVED_VA", true, handle_arg_reserved_va,
>> "size", "reserve 'size' bytes for guest virtual address space"},
>> {"d", "QEMU_LOG", true, handle_arg_log,
>> diff --git a/linux-user/mmap.c b/linux-user/mmap.c
>> index 8685f02e7e..3f35543acf 100644
>> --- a/linux-user/mmap.c
>> +++ b/linux-user/mmap.c
>> @@ -189,6 +189,7 @@ static int mmap_frag(abi_ulong real_start,
>> # define TASK_UNMAPPED_BASE 0x40000000
>> #endif
>> abi_ulong mmap_next_start = TASK_UNMAPPED_BASE;
>> +abi_ulong mmap_base = TASK_UNMAPPED_BASE;
>>
>> unsigned long last_brk;
>>
>> @@ -299,7 +300,7 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size,
>> abi_ulong align)
>>
>> if ((addr & (align - 1)) == 0) {
>> /* Success. */
>> - if (start == mmap_next_start && addr >= TASK_UNMAPPED_BASE)
>> {
>> + if (start == mmap_next_start && addr >= mmap_base) {
>> mmap_next_start = addr + size;
>> }
>> return addr;
>> diff --git a/linux-user/qemu.h b/linux-user/qemu.h
>> index 560a68090e..83c00cfea2 100644
>> --- a/linux-user/qemu.h
>> +++ b/linux-user/qemu.h
>> @@ -161,6 +161,11 @@ void task_settid(TaskState *);
>> void stop_all_tasks(void);
>> extern const char *qemu_uname_release;
>> extern unsigned long mmap_min_addr;
>> +/*
>> + * mmap_base is minimum address to use when allocating guest pages. All
>> guest
>> + * pages will be allocated at this (guest) address or higher addresses.
>> + */
>> +extern abi_ulong mmap_base;
>>
>> /* ??? See if we can avoid exposing so much of the loader internals. */
>>
>> --
>> 2.25.0.265.gbab2e86ba0-goog
>>
>
> Friendly ping~
>
> Link to the page for the patch on patchwork:
> http://patchwork.ozlabs.org/patch/1242370/
>
