On 28/09/2021 21:30, Bobby Eshleman wrote:
> diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
> index e60af16ddd..772e2a5bfc 100644
> --- a/xen/arch/x86/traps.c
> +++ b/xen/arch/x86/traps.c
> @@ -858,13 +858,20 @@ static void do_trap(struct cpu_user_regs *regs)
> if ( regs->error_code & X86_XEC_EXT )
> goto hardware_trap;
>
> - if ( debugger_trap_entry(trapnr, regs) )
> - return;
> -
> ASSERT(trapnr < 32);
>
> if ( guest_mode(regs) )
> {
> + struct vcpu *curr = current;
> + if ( (trapnr == TRAP_debug || trapnr == TRAP_int3) &&
> + guest_kernel_mode(curr, regs) &&
> + curr->domain->debugger_attached )
> + {
> + if ( trapnr != TRAP_debug )
> + curr->arch.gdbsx_vcpu_event = trapnr;
> + domain_pause_for_debugger();
> + return;
> + }
This is unreachable. do_trap() isn't used for TRAP_debug or TRAP_int3.
> @@ -2014,9 +2021,6 @@ void do_entry_CP(struct cpu_user_regs *regs)
> const char *err = "??";
> unsigned int ec = regs->error_code;
>
> - if ( debugger_trap_entry(TRAP_debug, regs) )
> - return;
> -
> /* Decode ec if possible */
> if ( ec < ARRAY_SIZE(errors) && errors[ec][0] )
> err = errors[ec];
> @@ -2028,6 +2032,12 @@ void do_entry_CP(struct cpu_user_regs *regs)
> */
> if ( guest_mode(regs) )
> {
> + struct vcpu *curr = current;
> + if ( guest_kernel_mode(curr, regs) &&
> curr->domain->debugger_attached )
> + {
> + domain_pause_for_debugger();
> + return;
> + }
Urgh. The TRAP_debug above was a copy/paste error.
I'll submit a patch, as it wants backporting for a couple of releases,
after which there should be no additions in do_entry_CP().
Everything else looks good.
~Andrew
