| Message ID | 1454256948-10485-2-git-send-email-serge.fdrv@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 31 January 2016 at 16:15, Sergey Fedorov <serge.fdrv@gmail.com> wrote: > When QEMU watchpoint matches, that is not definitely an architectural > watchpoint match yet. If it is a stop-before-access watchpoint then that > is hardly possible to ignore it after throwing a TCG exception. > > A special callback is introduced to check for architectural watchpoint > match before raising a TCG exception. > > Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com> This looks OK to me, but there's one QOM CPU style question I'd like Andreas's view on. > @@ -2024,6 +2024,7 @@ static const MemoryRegionOps notdirty_mem_ops = { > static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) > { > CPUState *cpu = current_cpu; > + CPUClass *cc = CPU_GET_CLASS(cpu); > CPUArchState *env = cpu->env_ptr; > target_ulong pc, cs_base; > target_ulong vaddr; > @@ -2049,6 +2050,11 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) > wp->hitaddr = vaddr; > wp->hitattrs = attrs; > if (!cpu->watchpoint_hit) { > + if (wp->flags & BP_CPU && > + !cc->debug_check_watchpoint(cpu, wp)) { At least some of the QOM CPU methods have wrapper functions (eg cpu_set_pc(), cpu_unaligned_access()) that just bundle up the CPU_GET_CLASS and method invocation). Should new methods like the debug_check_watchpoint() introduced by this patch have that kind of wrapper function, or is it optional? (There also seems to be a mix of "implement default/common behaviour in a common method implementation" vs "implement it in the wrapper function if the method pointer is NULL". I think the former, as done in this patch, is probably nicer but again would defer to Andreas.) thanks -- PMM
Andreas -- can I nudge you to say your preferences on whether QOM CPU methods should have wrapper functions, please? I think this patchset is otherwise ready to apply. thanks -- PMM On 2 February 2016 at 12:23, Peter Maydell <peter.maydell@linaro.org> wrote: > On 31 January 2016 at 16:15, Sergey Fedorov <serge.fdrv@gmail.com> wrote: >> When QEMU watchpoint matches, that is not definitely an architectural >> watchpoint match yet. If it is a stop-before-access watchpoint then that >> is hardly possible to ignore it after throwing a TCG exception. >> >> A special callback is introduced to check for architectural watchpoint >> match before raising a TCG exception. >> >> Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com> > > This looks OK to me, but there's one QOM CPU style question > I'd like Andreas's view on. > >> @@ -2024,6 +2024,7 @@ static const MemoryRegionOps notdirty_mem_ops = { >> static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) >> { >> CPUState *cpu = current_cpu; >> + CPUClass *cc = CPU_GET_CLASS(cpu); >> CPUArchState *env = cpu->env_ptr; >> target_ulong pc, cs_base; >> target_ulong vaddr; >> @@ -2049,6 +2050,11 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) >> wp->hitaddr = vaddr; >> wp->hitattrs = attrs; >> if (!cpu->watchpoint_hit) { >> + if (wp->flags & BP_CPU && >> + !cc->debug_check_watchpoint(cpu, wp)) { > > At least some of the QOM CPU methods have wrapper functions > (eg cpu_set_pc(), cpu_unaligned_access()) that just bundle up > the CPU_GET_CLASS and method invocation). Should new methods > like the debug_check_watchpoint() introduced by this patch have > that kind of wrapper function, or is it optional? > > (There also seems to be a mix of "implement default/common > behaviour in a common method implementation" vs "implement > it in the wrapper function if the method pointer is NULL". > I think the former, as done in this patch, is probably nicer > but again would defer to Andreas.) > > thanks > -- PMM
On 8 February 2016 at 15:42, Peter Maydell <peter.maydell@linaro.org> wrote: > Andreas -- can I nudge you to say your preferences on whether > QOM CPU methods should have wrapper functions, please? > I think this patchset is otherwise ready to apply. Andreas tells me on IRC that he doesn't insist on wrapper functions, so I think this patch is fine as is. thanks -- PMM
diff --git a/exec.c b/exec.c index 9e076bc..14e7c76 100644 --- a/exec.c +++ b/exec.c @@ -2024,6 +2024,7 @@ static const MemoryRegionOps notdirty_mem_ops = { static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) { CPUState *cpu = current_cpu; + CPUClass *cc = CPU_GET_CLASS(cpu); CPUArchState *env = cpu->env_ptr; target_ulong pc, cs_base; target_ulong vaddr; @@ -2049,6 +2050,11 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) wp->hitaddr = vaddr; wp->hitattrs = attrs; if (!cpu->watchpoint_hit) { + if (wp->flags & BP_CPU && + !cc->debug_check_watchpoint(cpu, wp)) { + wp->flags &= ~BP_WATCHPOINT_HIT; + continue; + } cpu->watchpoint_hit = wp; tb_check_watchpoint(cpu); if (wp->flags & BP_STOP_BEFORE_ACCESS) { diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 035179c..984bc8d 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -64,6 +64,7 @@ typedef uint64_t vaddr; #define CPU_GET_CLASS(obj) OBJECT_GET_CLASS(CPUClass, (obj), TYPE_CPU) typedef struct CPUState CPUState; +typedef struct CPUWatchpoint CPUWatchpoint; typedef void (*CPUUnassignedAccess)(CPUState *cpu, hwaddr addr, bool is_write, bool is_exec, int opaque, @@ -106,6 +107,8 @@ struct TranslationBlock; * a memory access with the specified memory transaction attributes. * @gdb_read_register: Callback for letting GDB read a register. * @gdb_write_register: Callback for letting GDB write a register. + * @debug_check_watchpoint: Callback: return true if the architectural + * watchpoint whose address has matched should really fire. * @debug_excp_handler: Callback for handling debug exceptions. * @write_elf64_note: Callback for writing a CPU-specific ELF note to a * 64-bit VM coredump. @@ -165,6 +168,7 @@ typedef struct CPUClass { int (*asidx_from_attrs)(CPUState *cpu, MemTxAttrs attrs); int (*gdb_read_register)(CPUState *cpu, uint8_t *buf, int reg); int (*gdb_write_register)(CPUState *cpu, uint8_t *buf, int reg); + bool (*debug_check_watchpoint)(CPUState *cpu, CPUWatchpoint *wp); void (*debug_excp_handler)(CPUState *cpu); int (*write_elf64_note)(WriteCoreDumpFunction f, CPUState *cpu, diff --git a/qom/cpu.c b/qom/cpu.c index 8f537a4..5a6a47e 100644 --- a/qom/cpu.c +++ b/qom/cpu.c @@ -188,6 +188,14 @@ static int cpu_common_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg) return 0; } +static bool cpu_common_debug_check_watchpoint(CPUState *cpu, CPUWatchpoint *wp) +{ + /* If no extra check is required, QEMU watchpoint match can be considered + * as an architectural match. + */ + return true; +} + bool target_words_bigendian(void); static bool cpu_common_virtio_is_big_endian(CPUState *cpu) { @@ -352,6 +360,7 @@ static void cpu_class_init(ObjectClass *klass, void *data) k->gdb_write_register = cpu_common_gdb_write_register; k->virtio_is_big_endian = cpu_common_virtio_is_big_endian; k->debug_excp_handler = cpu_common_noop; + k->debug_check_watchpoint = cpu_common_debug_check_watchpoint; k->cpu_exec_enter = cpu_common_noop; k->cpu_exec_exit = cpu_common_noop; k->cpu_exec_interrupt = cpu_common_exec_interrupt;
When QEMU watchpoint matches, that is not definitely an architectural watchpoint match yet. If it is a stop-before-access watchpoint then that is hardly possible to ignore it after throwing a TCG exception. A special callback is introduced to check for architectural watchpoint match before raising a TCG exception. Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com> --- exec.c | 6 ++++++ include/qom/cpu.h | 4 ++++ qom/cpu.c | 9 +++++++++ 3 files changed, 19 insertions(+)