Re: [Qemu-devel] [PATCH v9 26/27] gdbstub: Add support to read a MSR for KVM target

[Alex Bennée]

Jon Doron <address@hidden> writes:

> Ah cool did not know about that I will look into it and perhaps can do
> a different patchset just for this no need to add it on top of this
> patchset

Yes just drop these arch specific patches for your next iteration while
you rework them for the target/ approach. Hopefully we'll have the
re-factor merged before you've finished.

>
> On Wed, May 15, 2019 at 8:48 PM Alex Bennée <address@hidden> wrote:
>>
>>
>> Jon Doron <address@hidden> writes:
>>
>> > gdb> maint packet qqemu.kvm.Rdmsr:MsrIndex
>>
>> gdbserver already has a mechanism for exposing system registers see:
>>
>>   commit 200bf5b7ffea635079cc05fdfb363372b9544ce7
>>   Author: Abdallah Bouassida <address@hidden>
>>   Date:   Fri May 18 17:48:07 2018 +0100
>>
>> for an example. As MSR's are very specific to x86 all this should be
>> handled via target/i386/gdbstub and kept out of the generic code.
>>
>> >
>> > Signed-off-by: Jon Doron <address@hidden>
>> > ---
>> >  gdbstub.c | 38 +++++++++++++++++++++++++++++++++++++-
>> >  1 file changed, 37 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/gdbstub.c b/gdbstub.c
>> > index 34da10260d..f48c3a2b5f 100644
>> > --- a/gdbstub.c
>> > +++ b/gdbstub.c
>> > @@ -2141,7 +2141,14 @@ static void handle_query_attached(GdbCmdContext 
>> > *gdb_ctx, void *user_ctx)
>> >
>> >  static void handle_query_qemu_supported(GdbCmdContext *gdb_ctx, void 
>> > *user_ctx)
>> >  {
>> > -    put_packet(gdb_ctx->s, "sstepbits;sstep;PhyMemMode");
>> > +    snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf),
>> > +             "sstepbits;sstep;PhyMemMode");
>> > +
>> > +    if (kvm_enabled()) {
>> > +        pstrcat(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), ";kvm.Rdmsr");
>> > +    }
>> > +
>> > +    put_packet(gdb_ctx->s, gdb_ctx->str_buf);
>> >  }
>> >
>> >  static void handle_query_qemu_phy_mem_mode(GdbCmdContext *gdb_ctx,
>> > @@ -2166,6 +2173,29 @@ static void 
>> > handle_set_qemu_phy_mem_mode(GdbCmdContext *gdb_ctx, void *user_ctx)
>> >      put_packet(gdb_ctx->s, "OK");
>> >  }
>> >
>> > +static void handle_query_kvm_read_msr(GdbCmdContext *gdb_ctx, void 
>> > *user_ctx)
>> > +{
>> > +    uint64_t msr_val;
>> > +
>> > +    if (!kvm_enabled()) {
>> > +        return;
>> > +    }
>> > +
>> > +    if (!gdb_ctx->num_params) {
>> > +        put_packet(gdb_ctx->s, "E22");
>> > +        return;
>> > +    }
>> > +
>> > +    if (kvm_arch_read_msr(gdbserver_state->c_cpu, 
>> > gdb_ctx->params[0].val_ul,
>> > +                          &msr_val)) {
>> > +        put_packet(gdb_ctx->s, "E00");
>> > +        return;
>> > +    }
>> > +
>> > +    snprintf(gdb_ctx->str_buf, sizeof(gdb_ctx->str_buf), "0x%" PRIx64, 
>> > msr_val);
>> > +    put_packet(gdb_ctx->s, gdb_ctx->str_buf);
>> > +}
>> > +
>> >  static GdbCmdParseEntry gdb_gen_query_set_common_table[] = {
>> >      /* Order is important if has same prefix */
>> >      {
>> > @@ -2250,6 +2280,12 @@ static GdbCmdParseEntry gdb_gen_query_table[] = {
>> >          .handler = handle_query_qemu_phy_mem_mode,
>> >          .cmd = "qemu.PhyMemMode",
>> >      },
>> > +    {
>> > +        .handler = handle_query_kvm_read_msr,
>> > +        .cmd = "qemu.kvm.Rdmsr:",
>> > +        .cmd_startswith = 1,
>> > +        .schema = "l0"
>> > +    },
>> >  };
>> >
>> >  static GdbCmdParseEntry gdb_gen_set_table[] = {
>>
>>
>> --
>> Alex Bennée


--
Alex Bennée