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Subject: Re: [patch V4 part 5 05/31] x86/entry: Switch XEN/PV hypercall entry
 to IDTENTRY
To:     Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     x86@kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Juergen Gross <jgross@suse.com>,
        Brian Gerst <brgerst@gmail.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Will Deacon <will@kernel.org>
References: <20200505135341.730586321@linutronix.de>
 <20200505135828.592598658@linutronix.de>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Message-ID: <5418e98e-b293-bff3-2c74-c7f932c09c55@oracle.com>
Date:   Wed, 6 May 2020 22:11:06 -0400
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On 5/5/20 9:53 AM, Thomas Gleixner wrote:
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -20,6 +20,7 @@
>  #include <asm/setup.h>
>  #include <asm/acpi.h>
>  #include <asm/numa.h>
> +#include <asm/idtentry.h>
>  #include <asm/xen/hypervisor.h>
>  #include <asm/xen/hypercall.h>
> =20
> @@ -993,7 +994,8 @@ static void __init xen_pvmmu_arch_setup(
>  	HYPERVISOR_vm_assist(VMASST_CMD_enable,
>  			     VMASST_TYPE_pae_extended_cr3);
> =20
> -	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||=

> +	if (register_callback(CALLBACKTYPE_event,
> +			      asm_exc_xen_hypervisor_callback) ||


This ...


>  	    register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
>  		BUG();
> =20
> --- a/arch/x86/xen/smp_pv.c
> +++ b/arch/x86/xen/smp_pv.c
> @@ -27,6 +27,7 @@
>  #include <asm/paravirt.h>
>  #include <asm/desc.h>
>  #include <asm/pgtable.h>
> +#include <asm/idtentry.h>
>  #include <asm/cpu.h>
> =20
>  #include <xen/interface/xen.h>
> @@ -347,7 +348,7 @@ cpu_initialize_context(unsigned int cpu,
>  	ctxt->gs_base_kernel =3D per_cpu_offset(cpu);
>  #endif
>  	ctxt->event_callback_eip    =3D
> -		(unsigned long)xen_hypervisor_callback;
> +		(unsigned long)asm_exc_xen_hypervisor_callback;


=2E.. and this should be xen_asm_exc_xen_hypervisor_callback (we need to
pop %rcx and %r11).


And then Xen PV guest boots.


-boris


>  	ctxt->failsafe_callback_eip =3D
>  		(unsigned long)xen_failsafe_callback;
>  	per_cpu(xen_cr3, cpu) =3D __pa(swapper_pg_dir);