On Wed, 2021-10-13 at 16:50 +0100, Alex Bennée wrote:
> Maxim Levitsky <mlevitsk@xxxxxxxxxx> writes:
>
> > Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
> > ---
> > accel/kvm/kvm-all.c | 25 ++++++++++++++++++
> > gdbstub.c | 60 ++++++++++++++++++++++++++++++++++++--------
> > include/sysemu/kvm.h | 13 ++++++++++
> > 3 files changed, 88 insertions(+), 10 deletions(-)
> >
> > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> > index 6b187e9c96..e141260796 100644
> > --- a/accel/kvm/kvm-all.c
> > +++ b/accel/kvm/kvm-all.c
> > @@ -169,6 +169,8 @@ bool kvm_vm_attributes_allowed;
> > bool kvm_direct_msi_allowed;
> > bool kvm_ioeventfd_any_length_allowed;
> > bool kvm_msi_use_devid;
> > +bool kvm_has_guest_debug;
> > +int kvm_sstep_flags;
> > static bool kvm_immediate_exit;
> > static hwaddr kvm_max_slot_size = ~0;
> >
> > @@ -2559,6 +2561,25 @@ static int kvm_init(MachineState *ms)
> > kvm_sregs2 =
> > (kvm_check_extension(s, KVM_CAP_SREGS2) > 0);
> >
> > + kvm_has_guest_debug =
> > + (kvm_check_extension(s, KVM_CAP_SET_GUEST_DEBUG) > 0);
> > +
> > + kvm_sstep_flags = 0;
> > +
> > + if (kvm_has_guest_debug) {
> > + /* Assume that single stepping is supported */
> > + kvm_sstep_flags = SSTEP_ENABLE;
> > +
> > + int guest_debug_flags =
> > + kvm_check_extension(s, KVM_CAP_SET_GUEST_DEBUG2);
> > +
> > + if (guest_debug_flags > 0) {
> > + if (guest_debug_flags & KVM_GUESTDBG_BLOCKIRQ) {
> > + kvm_sstep_flags |= SSTEP_NOIRQ;
> > + }
> > + }
> > + }
> > +
> > kvm_state = s;
> >
> > ret = kvm_arch_init(ms, s);
> > @@ -3188,6 +3209,10 @@ int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
> >
> > if (cpu->singlestep_enabled) {
> > data.dbg.control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
> > +
> > + if (cpu->singlestep_enabled & SSTEP_NOIRQ) {
> > + data.dbg.control |= KVM_GUESTDBG_BLOCKIRQ;
> > + }
> > }
> > kvm_arch_update_guest_debug(cpu, &data.dbg);
> >
> > diff --git a/gdbstub.c b/gdbstub.c
> > index 5d8e6ae3cd..48bb803bae 100644
> > --- a/gdbstub.c
> > +++ b/gdbstub.c
> > @@ -368,12 +368,11 @@ typedef struct GDBState {
> > gdb_syscall_complete_cb current_syscall_cb;
> > GString *str_buf;
> > GByteArray *mem_buf;
> > + int sstep_flags;
> > + int supported_sstep_flags;
> > } GDBState;
> >
> > -/* By default use no IRQs and no timers while single stepping so as to
> > - * make single stepping like an ICE HW step.
> > - */
> > -static int sstep_flags = SSTEP_ENABLE|SSTEP_NOIRQ|SSTEP_NOTIMER;
> > +static GDBState gdbserver_state;
> >
> > /* Retrieves flags for single step mode. */
> > static int get_sstep_flags(void)
> > @@ -385,11 +384,10 @@ static int get_sstep_flags(void)
> > if (replay_mode != REPLAY_MODE_NONE) {
> > return SSTEP_ENABLE;
> > } else {
> > - return sstep_flags;
> > + return gdbserver_state.sstep_flags;
> > }
> > }
> >
> > -static GDBState gdbserver_state;
> >
> > static void init_gdbserver_state(void)
> > {
> > @@ -399,6 +397,23 @@ static void init_gdbserver_state(void)
> > gdbserver_state.str_buf = g_string_new(NULL);
> > gdbserver_state.mem_buf = g_byte_array_sized_new(MAX_PACKET_LENGTH);
> > gdbserver_state.last_packet = g_byte_array_sized_new(MAX_PACKET_LENGTH + 4);
> > +
> > +
> > + if (kvm_enabled()) {
> > + gdbserver_state.supported_sstep_flags = kvm_get_supported_sstep_flags();
> > + } else {
> > + gdbserver_state.supported_sstep_flags =
> > + SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER;
> > + }
>
> This fails to build:
>
> o -c ../../gdbstub.c
> ../../gdbstub.c: In function ‘init_gdbserver_state’:
> ../../gdbstub.c:403:49: error: implicit declaration of function ‘kvm_get_supported_sstep_flags’ [-Werror=implicit-function-declaration]
> 403 | gdbserver_state.supported_sstep_flags = kvm_get_supported_sstep_flags();
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../gdbstub.c:403:49: error: nested extern declaration of ‘kvm_get_supported_sstep_flags’ [-Werror=nested-externs]
> ../../gdbstub.c: In function ‘gdbserver_start’:
> ../../gdbstub.c:3531:27: error: implicit declaration of function ‘kvm_supports_guest_debug’; did you mean ‘kvm_update_guest_debug’? [-Werror=implicit-function-declaration]
> 3531 | if (kvm_enabled() && !kvm_supports_guest_debug()) {
> | ^~~~~~~~~~~~~~~~~~~~~~~~
> | kvm_update_guest_debug
> ../../gdbstub.c:3531:27: error: nested extern declaration of ‘kvm_supports_guest_debug’ [-Werror=nested-externs]
> cc1: all warnings being treated as errors
>
> In fact looking back I can see I mentioned this last time:
>
> Subject: Re: [PATCH 2/2] gdbstub: implement NOIRQ support for single step on
> KVM, when kvm's KVM_GUESTDBG_BLOCKIRQ debug flag is supported.
> Date: Mon, 19 Apr 2021 17:29:25 +0100
> In-reply-to: <20210401144152.1031282-3-mlevitsk@xxxxxxxxxx>
> Message-ID: <871rb69qqk.fsf@xxxxxxxxxx>
>
> Please in future could you include a revision number for your spin and
> mention bellow the --- what changes have been made since the last
> posting.
You mean it fails to build without KVM? I swear I tested build with TTG only after you mentioned this
(or as it seems I only tried to).
Could you give me the ./configure parameters you used?
Sorry for this!
Best regards,
Maxim Levitsky
>
>
