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linux-next: manual merge of the xen-tip tree with the tip tree

Message ID alpine.DEB.2.20.1708311057260.1874@nanos (mailing list archive)
State New, archived
Headers show

Commit Message

Thomas Gleixner Aug. 31, 2017, 9 a.m. UTC
On Thu, 31 Aug 2017, Thomas Gleixner wrote:
> Hrm. For some reason I missed to remove these defines after getting rid of
> the tracing idt.
> 
> I'll remove that now in tip and pull in the XEN stuff to see what needs to
> be done.

I pushed out the removal of the trace leftovers. Talked to Juergen on IRC
and he suggested to revert the XEN patch in the xen tree and merge it
through tip.

I've applied it on top of tip:x86/apic and fixed up the merge conflicts
mindlessly. Patch below.

Juergen, can you please check the result?

Thanks,

	tglx

8<-------------
Subject: xen: Get rid of paravirt op adjust_exception_frame
From: Juergen Gross <jgross@suse.com>
Date: Fri, 11 Aug 2017 16:54:48 +0200

When running as Xen pv-guest the exception frame on the stack contains
%r11 and %rcx additional to the other data pushed by the processor.

Instead of having a paravirt op being called for each exception type
prepend the Xen specific code to each exception entry. When running as
Xen pv-guest just use the exception entry with prepended instructions,
otherwise use the entry without the Xen specific code.

Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/20170811145448.5679-1-jgross@suse.com

---
 arch/x86/entry/entry_64.S             |   11 +--
 arch/x86/entry/entry_64_compat.S      |    1 
 arch/x86/include/asm/paravirt.h       |    5 -
 arch/x86/include/asm/paravirt_types.h |    4 -
 arch/x86/include/asm/proto.h          |    3 +
 arch/x86/include/asm/traps.h          |    3 -
 arch/x86/kernel/asm-offsets_64.c      |    1 
 arch/x86/kernel/paravirt.c            |    3 -
 arch/x86/xen/enlighten_pv.c           |   96 ++++++++++++++++++++++------------
 arch/x86/xen/irq.c                    |    3 -
 arch/x86/xen/xen-ops.h                |    1 
 11 files changed, 70 insertions(+), 61 deletions(-)

Comments

Ingo Molnar Aug. 31, 2017, 9:16 a.m. UTC | #1
* Thomas Gleixner <tglx@linutronix.de> wrote:

> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -586,6 +586,68 @@ static void xen_write_ldt_entry(struct d
>  	preempt_enable();
>  }
>  
> +#ifdef CONFIG_X86_64
> +static struct {
> +	void (*orig)(void);
> +	void (*xen)(void);
> +	bool ist_okay;
> +} trap_array[] = {
> +	{ debug, xen_xendebug, true },
> +	{ int3, xen_xenint3, true },
> +	{ double_fault, xen_double_fault, true },
> +#ifdef CONFIG_X86_MCE
> +	{ machine_check, xen_machine_check, true },
> +#endif
> +	{ nmi, xen_nmi, true },
> +	{ overflow, xen_overflow, false },
> +#ifdef CONFIG_IA32_EMULATION
> +	{ entry_INT80_compat, xen_entry_INT80_compat, false },
> +#endif
> +	{ page_fault, xen_page_fault, false },
> +	{ divide_error, xen_divide_error, false },
> +	{ bounds, xen_bounds, false },
> +	{ invalid_op, xen_invalid_op, false },
> +	{ device_not_available, xen_device_not_available, false },
> +	{ coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
> +	{ invalid_TSS, xen_invalid_TSS, false },
> +	{ segment_not_present, xen_segment_not_present, false },
> +	{ stack_segment, xen_stack_segment, false },
> +	{ general_protection, xen_general_protection, false },
> +	{ spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
> +	{ coprocessor_error, xen_coprocessor_error, false },
> +	{ alignment_check, xen_alignment_check, false },
> +	{ simd_coprocessor_error, xen_simd_coprocessor_error, false },
> +#ifdef CONFIG_TRACING
> +	{ trace_page_fault, xen_trace_page_fault, false },
> +#endif
> +};

Low prio nitpicking, could we please write such table based initializers in a 
vertically organized, tabular fashion:

> +	{ debug,			xen_xendebug,				true },
> +	{ int3,				xen_xenint3,				true },
> +	{ double_fault,			xen_double_fault,			true },
> +#ifdef CONFIG_X86_MCE
> +	{ machine_check,		xen_machine_check,			true },
> +#endif
> +	{ nmi,				xen_nmi,				true },
> +	{ overflow,			xen_overflow,				false },
> +#ifdef CONFIG_IA32_EMULATION
> +	{ entry_INT80_compat,		xen_entry_INT80_compat,			false },
> +#endif
> +	{ page_fault,			xen_page_fault,				false },
> +	{ divide_error,			xen_divide_error,			false },
> +	{ bounds,			xen_bounds,				false },
> +	{ invalid_op,			xen_invalid_op,				false },
> +	{ device_not_available,		xen_device_not_available,		false },
> +	{ coprocessor_segment_overrun,	xen_coprocessor_segment_overrun,	false },
> +	{ invalid_TSS,			xen_invalid_TSS,			false },
> +	{ segment_not_present,		xen_segment_not_present,		false },
> +	{ stack_segment,		xen_stack_segment,			false },
> +	{ general_protection,		xen_general_protection,			false },
> +	{ spurious_interrupt_bug,	xen_spurious_interrupt_bug,		false },
> +	{ coprocessor_error,		xen_coprocessor_error,			false },
> +	{ alignment_check,		xen_alignment_check,			false },
> +	{ simd_coprocessor_error,	xen_simd_coprocessor_error,		false },
> +#ifdef CONFIG_TRACING
> +	{ trace_page_fault,		xen_trace_page_fault,			false },
> +#endif

... as to me such a table is 100 times more readable - YMMV.

(If checkpatch whinges about col80 then ignore it.)

> +
> +static bool get_trap_addr(unsigned long *addr, unsigned int ist)
> +{
> +	unsigned int nr;
> +	bool ist_okay = false;
> +
> +	/*
> +	 * Replace trap handler addresses by Xen specific ones.
> +	 * Check for known traps using IST and whitelist them.
> +	 * The debugger ones are the only ones we care about.
> +	 * Xen will handle faults like double_fault, * so we should never see
> +	 * them.  Warn if there's an unexpected IST-using fault handler.
> +	 */
> +	for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++)
> +		if (*addr == (unsigned long)trap_array[nr].orig) {
> +			*addr = (unsigned long)trap_array[nr].xen;
> +			ist_okay = trap_array[nr].ist_okay;
> +			break;
> +		}

And here I think we could do a more readable variant:

  static bool get_trap_addr(void **addr, unsigned int ist)
  ...
		struct trap_array_entry *entry = trap_array + nr;

		if (*addr == entry->orig) {
			*addr = entry->xen;
			ist_okay = entry->ist_okay;
			break;
		}

I believe 'void **' is the natural type that avoids the type casts, and the 
'trap_array_entry' name has to be defined in the array definition further above.

Totally untested though.

Thanks,

	Ingo
Jürgen Groß Aug. 31, 2017, 10:11 a.m. UTC | #2
On 31/08/17 11:00, Thomas Gleixner wrote:
> On Thu, 31 Aug 2017, Thomas Gleixner wrote:
>> Hrm. For some reason I missed to remove these defines after getting rid of
>> the tracing idt.
>>
>> I'll remove that now in tip and pull in the XEN stuff to see what needs to
>> be done.
> 
> I pushed out the removal of the trace leftovers. Talked to Juergen on IRC
> and he suggested to revert the XEN patch in the xen tree and merge it
> through tip.
> 
> I've applied it on top of tip:x86/apic and fixed up the merge conflicts
> mindlessly. Patch below.
> 
> Juergen, can you please check the result?
> 
> Thanks,
> 
> 	tglx
> 
> 8<-------------
> Subject: xen: Get rid of paravirt op adjust_exception_frame
> From: Juergen Gross <jgross@suse.com>
> Date: Fri, 11 Aug 2017 16:54:48 +0200
> 
> When running as Xen pv-guest the exception frame on the stack contains
> %r11 and %rcx additional to the other data pushed by the processor.
> 
> Instead of having a paravirt op being called for each exception type
> prepend the Xen specific code to each exception entry. When running as
> Xen pv-guest just use the exception entry with prepended instructions,
> otherwise use the entry without the Xen specific code.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Cc: xen-devel@lists.xenproject.org
> Cc: boris.ostrovsky@oracle.com
> Cc: luto@amacapital.net
> Link: http://lkml.kernel.org/r/20170811145448.5679-1-jgross@suse.com
> 
> ---
>  arch/x86/entry/entry_64.S             |   11 +--
>  arch/x86/entry/entry_64_compat.S      |    1 
>  arch/x86/include/asm/paravirt.h       |    5 -
>  arch/x86/include/asm/paravirt_types.h |    4 -
>  arch/x86/include/asm/proto.h          |    3 +
>  arch/x86/include/asm/traps.h          |    3 -
>  arch/x86/kernel/asm-offsets_64.c      |    1 
>  arch/x86/kernel/paravirt.c            |    3 -
>  arch/x86/xen/enlighten_pv.c           |   96 ++++++++++++++++++++++------------
>  arch/x86/xen/irq.c                    |    3 -
>  arch/x86/xen/xen-ops.h                |    1 
>  11 files changed, 70 insertions(+), 61 deletions(-)
> 
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -816,7 +816,6 @@ ENTRY(\sym)
>  	.endif
>  
>  	ASM_CLAC
> -	PARAVIRT_ADJUST_EXCEPTION_FRAME
>  
>  	.ifeq \has_error_code
>  	pushq	$-1				/* ORIG_RAX: no syscall to restart */
> @@ -962,7 +961,7 @@ ENTRY(do_softirq_own_stack)
>  ENDPROC(do_softirq_own_stack)
>  
>  #ifdef CONFIG_XEN
> -idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0
> +idtentry hypervisor_callback xen_do_hypervisor_callback has_error_code=0
>  
>  /*
>   * A note on the "critical region" in our callback handler.
> @@ -1029,8 +1028,6 @@ ENTRY(xen_failsafe_callback)
>  	movq	8(%rsp), %r11
>  	addq	$0x30, %rsp
>  	pushq	$0				/* RIP */
> -	pushq	%r11
> -	pushq	%rcx
>  	UNWIND_HINT_IRET_REGS offset=8
>  	jmp	general_protection
>  1:	/* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
> @@ -1061,9 +1058,8 @@ idtentry int3			do_int3			has_error_code
>  idtentry stack_segment		do_stack_segment	has_error_code=1
>  
>  #ifdef CONFIG_XEN
> -idtentry xen_debug		do_debug		has_error_code=0
> -idtentry xen_int3		do_int3			has_error_code=0
> -idtentry xen_stack_segment	do_stack_segment	has_error_code=1
> +idtentry xendebug		do_debug		has_error_code=0
> +idtentry xenint3		do_int3			has_error_code=0
>  #endif
>  
>  idtentry general_protection	do_general_protection	has_error_code=1
> @@ -1227,6 +1223,7 @@ ENTRY(error_exit)
>  END(error_exit)
>  
>  /* Runs on exception stack */
> +/* XXX: broken on Xen PV */
>  ENTRY(nmi)
>  	UNWIND_HINT_IRET_REGS
>  	/*
> --- a/arch/x86/entry/entry_64_compat.S
> +++ b/arch/x86/entry/entry_64_compat.S
> @@ -293,7 +293,6 @@ ENTRY(entry_INT80_compat)
>  	/*
>  	 * Interrupts are off on entry.
>  	 */
> -	PARAVIRT_ADJUST_EXCEPTION_FRAME
>  	ASM_CLAC			/* Do this early to minimize exposure */
>  	SWAPGS
>  
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -960,11 +960,6 @@ extern void default_banner(void);
>  #define GET_CR2_INTO_RAX				\
>  	call PARA_INDIRECT(pv_mmu_ops+PV_MMU_read_cr2)
>  
> -#define PARAVIRT_ADJUST_EXCEPTION_FRAME					\
> -	PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_adjust_exception_frame), \
> -		  CLBR_NONE,						\
> -		  call PARA_INDIRECT(pv_irq_ops+PV_IRQ_adjust_exception_frame))
> -
>  #define USERGS_SYSRET64							\
>  	PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64),	\
>  		  CLBR_NONE,						\
> --- a/arch/x86/include/asm/paravirt_types.h
> +++ b/arch/x86/include/asm/paravirt_types.h
> @@ -195,10 +195,6 @@ struct pv_irq_ops {
>  
>  	void (*safe_halt)(void);
>  	void (*halt)(void);
> -
> -#ifdef CONFIG_X86_64
> -	void (*adjust_exception_frame)(void);
> -#endif
>  } __no_randomize_layout;
>  
>  struct pv_mmu_ops {
> --- a/arch/x86/include/asm/proto.h
> +++ b/arch/x86/include/asm/proto.h
> @@ -24,6 +24,9 @@ void entry_SYSENTER_compat(void);
>  void __end_entry_SYSENTER_compat(void);
>  void entry_SYSCALL_compat(void);
>  void entry_INT80_compat(void);
> +#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
> +void xen_entry_INT80_compat(void);
> +#endif
>  #endif
>  
>  void x86_configure_nx(void);
> --- a/arch/x86/include/asm/traps.h
> +++ b/arch/x86/include/asm/traps.h
> @@ -13,9 +13,6 @@ asmlinkage void divide_error(void);
>  asmlinkage void debug(void);
>  asmlinkage void nmi(void);
>  asmlinkage void int3(void);
> -asmlinkage void xen_debug(void);
> -asmlinkage void xen_int3(void);
> -asmlinkage void xen_stack_segment(void);
>  asmlinkage void overflow(void);
>  asmlinkage void bounds(void);
>  asmlinkage void invalid_op(void);
> --- a/arch/x86/kernel/asm-offsets_64.c
> +++ b/arch/x86/kernel/asm-offsets_64.c
> @@ -20,7 +20,6 @@ static char syscalls_ia32[] = {
>  int main(void)
>  {
>  #ifdef CONFIG_PARAVIRT
> -	OFFSET(PV_IRQ_adjust_exception_frame, pv_irq_ops, adjust_exception_frame);
>  	OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
>  	OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
>  	BLANK();
> --- a/arch/x86/kernel/paravirt.c
> +++ b/arch/x86/kernel/paravirt.c
> @@ -319,9 +319,6 @@ struct pv_time_ops pv_time_ops = {
>  	.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
>  	.safe_halt = native_safe_halt,
>  	.halt = native_halt,
> -#ifdef CONFIG_X86_64
> -	.adjust_exception_frame = paravirt_nop,
> -#endif
>  };
>  
>  __visible struct pv_cpu_ops pv_cpu_ops = {
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -586,6 +586,68 @@ static void xen_write_ldt_entry(struct d
>  	preempt_enable();
>  }
>  
> +#ifdef CONFIG_X86_64
> +static struct {
> +	void (*orig)(void);
> +	void (*xen)(void);
> +	bool ist_okay;
> +} trap_array[] = {
> +	{ debug, xen_xendebug, true },
> +	{ int3, xen_xenint3, true },
> +	{ double_fault, xen_double_fault, true },
> +#ifdef CONFIG_X86_MCE
> +	{ machine_check, xen_machine_check, true },
> +#endif
> +	{ nmi, xen_nmi, true },
> +	{ overflow, xen_overflow, false },
> +#ifdef CONFIG_IA32_EMULATION
> +	{ entry_INT80_compat, xen_entry_INT80_compat, false },
> +#endif
> +	{ page_fault, xen_page_fault, false },
> +	{ divide_error, xen_divide_error, false },
> +	{ bounds, xen_bounds, false },
> +	{ invalid_op, xen_invalid_op, false },
> +	{ device_not_available, xen_device_not_available, false },
> +	{ coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
> +	{ invalid_TSS, xen_invalid_TSS, false },
> +	{ segment_not_present, xen_segment_not_present, false },
> +	{ stack_segment, xen_stack_segment, false },
> +	{ general_protection, xen_general_protection, false },
> +	{ spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
> +	{ coprocessor_error, xen_coprocessor_error, false },
> +	{ alignment_check, xen_alignment_check, false },
> +	{ simd_coprocessor_error, xen_simd_coprocessor_error, false },
> +#ifdef CONFIG_TRACING
> +	{ trace_page_fault, xen_trace_page_fault, false },
> +#endif
> +};
> +
> +static bool get_trap_addr(unsigned long *addr, unsigned int ist)
> +{
> +	unsigned int nr;
> +	bool ist_okay = false;
> +
> +	/*
> +	 * Replace trap handler addresses by Xen specific ones.
> +	 * Check for known traps using IST and whitelist them.
> +	 * The debugger ones are the only ones we care about.
> +	 * Xen will handle faults like double_fault, * so we should never see
> +	 * them.  Warn if there's an unexpected IST-using fault handler.
> +	 */
> +	for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++)
> +		if (*addr == (unsigned long)trap_array[nr].orig) {
> +			*addr = (unsigned long)trap_array[nr].xen;
> +			ist_okay = trap_array[nr].ist_okay;
> +			break;
> +		}
> +
> +	if (WARN_ON(ist != 0 && !ist_okay))
> +		return false;
> +
> +	return true;
> +}
> +#endif
> +
>  static int cvt_gate_to_trap(int vector, const gate_desc *val,
>  			    struct trap_info *info)
>  {
> @@ -598,40 +660,8 @@ static int cvt_gate_to_trap(int vector,
>  
>  	addr = gate_offset(val);
>  #ifdef CONFIG_X86_64
> -	/*
> -	 * Look for known traps using IST, and substitute them
> -	 * appropriately.  The debugger ones are the only ones we care
> -	 * about.  Xen will handle faults like double_fault,
> -	 * so we should never see them.  Warn if
> -	 * there's an unexpected IST-using fault handler.
> -	 */
> -	if (addr == (unsigned long)debug)
> -		addr = (unsigned long)xen_debug;
> -	else if (addr == (unsigned long)int3)
> -		addr = (unsigned long)xen_int3;
> -	else if (addr == (unsigned long)stack_segment)
> -		addr = (unsigned long)xen_stack_segment;
> -	else if (addr == (unsigned long)double_fault) {
> -		/* Don't need to handle these */
> +	if (!get_trap_addr(&addr, val->bits.ist))
>  		return 0;
> -#ifdef CONFIG_X86_MCE
> -	} else if (addr == (unsigned long)machine_check) {
> -		/*
> -		 * when xen hypervisor inject vMCE to guest,
> -		 * use native mce handler to handle it
> -		 */
> -		;
> -#endif
> -	} else if (addr == (unsigned long)nmi)
> -		/*
> -		 * Use the native version as well.
> -		 */
> -		;
> -	else {
> -		/* Some other trap using IST? */
> -		if (WARN_ON(val->bits.ist != 0))
> -			return 0;
> -	}
>  #endif	/* CONFIG_X86_64 */
>  	info->address = addr;
>  
> --- a/arch/x86/xen/irq.c
> +++ b/arch/x86/xen/irq.c
> @@ -123,9 +123,6 @@ static const struct pv_irq_ops xen_irq_o
>  
>  	.safe_halt = xen_safe_halt,
>  	.halt = xen_halt,
> -#ifdef CONFIG_X86_64
> -	.adjust_exception_frame = xen_adjust_exception_frame,
> -#endif
>  };
>  
>  void __init xen_init_irq_ops(void)
> --- a/arch/x86/xen/xen-ops.h
> +++ b/arch/x86/xen/xen-ops.h
> @@ -138,7 +138,6 @@ static inline void __init xen_efi_init(v
>  __visible void xen_iret(void);
>  __visible void xen_sysret32(void);
>  __visible void xen_sysret64(void);
> -__visible void xen_adjust_exception_frame(void);
>  
>  extern int xen_panic_handler_init(void);
>  
> 

You missed the updates to arch/x86/xen/xen-asm_64.S and the declarations
of the xen specific trap entries in arch/x86/include/asm/traps.h


Juergen
Thomas Gleixner Aug. 31, 2017, noon UTC | #3
On Thu, 31 Aug 2017, Juergen Gross wrote:
> > I've applied it on top of tip:x86/apic and fixed up the merge conflicts
> > mindlessly. Patch below.
> > 
> > Juergen, can you please check the result?
> 
> You missed the updates to arch/x86/xen/xen-asm_64.S and the declarations
> of the xen specific trap entries in arch/x86/include/asm/traps.h

I'll try that again later today, unless you beat me to it.

Thanks,

	tglx
Joe Perches Aug. 31, 2017, 12:36 p.m. UTC | #4
On Thu, 2017-08-31 at 11:16 +0200, Ingo Molnar wrote:
> * Thomas Gleixner <tglx@linutronix.de> wrote:
> Low prio nitpicking, could we please write such table based initializers in a 
> vertically organized, tabular fashion:
> 
> > +	{ debug,			xen_xendebug,				true },
> > +	{ int3,				xen_xenint3,				true },
> > +	{ double_fault,			xen_double_fault,			true },
> > +#ifdef CONFIG_X86_MCE
> > +	{ machine_check,		xen_machine_check,			true },
> > +#endif
> > +	{ nmi,				xen_nmi,				true },
> > +	{ overflow,			xen_overflow,				false },
> > +#ifdef CONFIG_IA32_EMULATION
> > +	{ entry_INT80_compat,		xen_entry_INT80_compat,			false },
> > +#endif
> > +	{ page_fault,			xen_page_fault,				false },
> > +	{ divide_error,			xen_divide_error,			false },
> > +	{ bounds,			xen_bounds,				false },
> > +	{ invalid_op,			xen_invalid_op,				false },
> > +	{ device_not_available,		xen_device_not_available,		false },
> > +	{ coprocessor_segment_overrun,	xen_coprocessor_segment_overrun,	false },
> > +	{ invalid_TSS,			xen_invalid_TSS,			false },
> > +	{ segment_not_present,		xen_segment_not_present,		false },
> > +	{ stack_segment,		xen_stack_segment,			false },
> > +	{ general_protection,		xen_general_protection,			false },
> > +	{ spurious_interrupt_bug,	xen_spurious_interrupt_bug,		false },
> > +	{ coprocessor_error,		xen_coprocessor_error,			false },
> > +	{ alignment_check,		xen_alignment_check,			false },
> > +	{ simd_coprocessor_error,	xen_simd_coprocessor_error,		false },
> > +#ifdef CONFIG_TRACING
> > +	{ trace_page_fault,		xen_trace_page_fault,			false },
> > +#endif
> ,,
> ... as to me such a table is 100 times more readable - YMMV.

Yeah, kinda.

It's a lot of whitespace and eyeball left/right scanning.
And these tables require whitespace updating if a longer
name is ever used.

Given the near 1:1 mapping of <trap> to xen_<trap>
perhaps adding a macro would be nice.

#define xen_trap(trap, ist_ok) \
	{ trap, xen_##trap, ist_ok }

	{ debug,	xen_xendebug,	true },
	{ int3,		xen_xenint3,	true },
#ifdef CONFIG_X86_MCE
	xen_trap(machine_check, true),
#endif
	xen_trap(double_fault, true),
	xen_trap(nmi, true),
	xen_trap(overflow, false),
	...

ymmv. </bikeshedding>
Boris Ostrovsky Aug. 31, 2017, 2:01 p.m. UTC | #5
On 08/31/2017 08:00 AM, Thomas Gleixner wrote:
> On Thu, 31 Aug 2017, Juergen Gross wrote:
>>> I've applied it on top of tip:x86/apic and fixed up the merge conflicts
>>> mindlessly. Patch below.
>>>
>>> Juergen, can you please check the result?
>> You missed the updates to arch/x86/xen/xen-asm_64.S and the declarations
>> of the xen specific trap entries in arch/x86/include/asm/traps.h
> I'll try that again later today, unless you beat me to it.
>

https://marc.info/?l=linux-kernel&m=150296063131595&w=2 should also be
picked up by the tip tree then since it applies on top of the
adjust_exception_frame patch. I will revert it from Xen tree as well.

-boris
Jürgen Groß Aug. 31, 2017, 2:03 p.m. UTC | #6
On 31/08/17 16:01, Boris Ostrovsky wrote:
> On 08/31/2017 08:00 AM, Thomas Gleixner wrote:
>> On Thu, 31 Aug 2017, Juergen Gross wrote:
>>>> I've applied it on top of tip:x86/apic and fixed up the merge conflicts
>>>> mindlessly. Patch below.
>>>>
>>>> Juergen, can you please check the result?
>>> You missed the updates to arch/x86/xen/xen-asm_64.S and the declarations
>>> of the xen specific trap entries in arch/x86/include/asm/traps.h
>> I'll try that again later today, unless you beat me to it.
>>
> 
> https://marc.info/?l=linux-kernel&m=150296063131595&w=2 should also be
> picked up by the tip tree then since it applies on top of the
> adjust_exception_frame patch. I will revert it from Xen tree as well.

I have included this patch in my rebase on top of the tip tree, so it is
no longer needed.


Juergen
Thomas Gleixner Aug. 31, 2017, 6:30 p.m. UTC | #7
On Thu, 31 Aug 2017, Boris Ostrovsky wrote:

> On 08/31/2017 08:00 AM, Thomas Gleixner wrote:
> > On Thu, 31 Aug 2017, Juergen Gross wrote:
> >>> I've applied it on top of tip:x86/apic and fixed up the merge conflicts
> >>> mindlessly. Patch below.
> >>>
> >>> Juergen, can you please check the result?
> >> You missed the updates to arch/x86/xen/xen-asm_64.S and the declarations
> >> of the xen specific trap entries in arch/x86/include/asm/traps.h
> > I'll try that again later today, unless you beat me to it.
> >
> 
> https://marc.info/?l=linux-kernel&m=150296063131595&w=2 should also be
> picked up by the tip tree then since it applies on top of the
> adjust_exception_frame patch. I will revert it from Xen tree as well.

Juergen folded that fix in and posted a version against tip:x86/apic. It's
applied and pushed out now.

Thanks to everyone helping with this.

       tglx
diff mbox

Patch

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -816,7 +816,6 @@  ENTRY(\sym)
 	.endif
 
 	ASM_CLAC
-	PARAVIRT_ADJUST_EXCEPTION_FRAME
 
 	.ifeq \has_error_code
 	pushq	$-1				/* ORIG_RAX: no syscall to restart */
@@ -962,7 +961,7 @@  ENTRY(do_softirq_own_stack)
 ENDPROC(do_softirq_own_stack)
 
 #ifdef CONFIG_XEN
-idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0
+idtentry hypervisor_callback xen_do_hypervisor_callback has_error_code=0
 
 /*
  * A note on the "critical region" in our callback handler.
@@ -1029,8 +1028,6 @@  ENTRY(xen_failsafe_callback)
 	movq	8(%rsp), %r11
 	addq	$0x30, %rsp
 	pushq	$0				/* RIP */
-	pushq	%r11
-	pushq	%rcx
 	UNWIND_HINT_IRET_REGS offset=8
 	jmp	general_protection
 1:	/* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */
@@ -1061,9 +1058,8 @@  idtentry int3			do_int3			has_error_code
 idtentry stack_segment		do_stack_segment	has_error_code=1
 
 #ifdef CONFIG_XEN
-idtentry xen_debug		do_debug		has_error_code=0
-idtentry xen_int3		do_int3			has_error_code=0
-idtentry xen_stack_segment	do_stack_segment	has_error_code=1
+idtentry xendebug		do_debug		has_error_code=0
+idtentry xenint3		do_int3			has_error_code=0
 #endif
 
 idtentry general_protection	do_general_protection	has_error_code=1
@@ -1227,6 +1223,7 @@  ENTRY(error_exit)
 END(error_exit)
 
 /* Runs on exception stack */
+/* XXX: broken on Xen PV */
 ENTRY(nmi)
 	UNWIND_HINT_IRET_REGS
 	/*
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -293,7 +293,6 @@  ENTRY(entry_INT80_compat)
 	/*
 	 * Interrupts are off on entry.
 	 */
-	PARAVIRT_ADJUST_EXCEPTION_FRAME
 	ASM_CLAC			/* Do this early to minimize exposure */
 	SWAPGS
 
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -960,11 +960,6 @@  extern void default_banner(void);
 #define GET_CR2_INTO_RAX				\
 	call PARA_INDIRECT(pv_mmu_ops+PV_MMU_read_cr2)
 
-#define PARAVIRT_ADJUST_EXCEPTION_FRAME					\
-	PARA_SITE(PARA_PATCH(pv_irq_ops, PV_IRQ_adjust_exception_frame), \
-		  CLBR_NONE,						\
-		  call PARA_INDIRECT(pv_irq_ops+PV_IRQ_adjust_exception_frame))
-
 #define USERGS_SYSRET64							\
 	PARA_SITE(PARA_PATCH(pv_cpu_ops, PV_CPU_usergs_sysret64),	\
 		  CLBR_NONE,						\
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -195,10 +195,6 @@  struct pv_irq_ops {
 
 	void (*safe_halt)(void);
 	void (*halt)(void);
-
-#ifdef CONFIG_X86_64
-	void (*adjust_exception_frame)(void);
-#endif
 } __no_randomize_layout;
 
 struct pv_mmu_ops {
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -24,6 +24,9 @@  void entry_SYSENTER_compat(void);
 void __end_entry_SYSENTER_compat(void);
 void entry_SYSCALL_compat(void);
 void entry_INT80_compat(void);
+#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
+void xen_entry_INT80_compat(void);
+#endif
 #endif
 
 void x86_configure_nx(void);
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -13,9 +13,6 @@  asmlinkage void divide_error(void);
 asmlinkage void debug(void);
 asmlinkage void nmi(void);
 asmlinkage void int3(void);
-asmlinkage void xen_debug(void);
-asmlinkage void xen_int3(void);
-asmlinkage void xen_stack_segment(void);
 asmlinkage void overflow(void);
 asmlinkage void bounds(void);
 asmlinkage void invalid_op(void);
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -20,7 +20,6 @@  static char syscalls_ia32[] = {
 int main(void)
 {
 #ifdef CONFIG_PARAVIRT
-	OFFSET(PV_IRQ_adjust_exception_frame, pv_irq_ops, adjust_exception_frame);
 	OFFSET(PV_CPU_usergs_sysret64, pv_cpu_ops, usergs_sysret64);
 	OFFSET(PV_CPU_swapgs, pv_cpu_ops, swapgs);
 	BLANK();
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -319,9 +319,6 @@  struct pv_time_ops pv_time_ops = {
 	.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
 	.safe_halt = native_safe_halt,
 	.halt = native_halt,
-#ifdef CONFIG_X86_64
-	.adjust_exception_frame = paravirt_nop,
-#endif
 };
 
 __visible struct pv_cpu_ops pv_cpu_ops = {
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -586,6 +586,68 @@  static void xen_write_ldt_entry(struct d
 	preempt_enable();
 }
 
+#ifdef CONFIG_X86_64
+static struct {
+	void (*orig)(void);
+	void (*xen)(void);
+	bool ist_okay;
+} trap_array[] = {
+	{ debug, xen_xendebug, true },
+	{ int3, xen_xenint3, true },
+	{ double_fault, xen_double_fault, true },
+#ifdef CONFIG_X86_MCE
+	{ machine_check, xen_machine_check, true },
+#endif
+	{ nmi, xen_nmi, true },
+	{ overflow, xen_overflow, false },
+#ifdef CONFIG_IA32_EMULATION
+	{ entry_INT80_compat, xen_entry_INT80_compat, false },
+#endif
+	{ page_fault, xen_page_fault, false },
+	{ divide_error, xen_divide_error, false },
+	{ bounds, xen_bounds, false },
+	{ invalid_op, xen_invalid_op, false },
+	{ device_not_available, xen_device_not_available, false },
+	{ coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
+	{ invalid_TSS, xen_invalid_TSS, false },
+	{ segment_not_present, xen_segment_not_present, false },
+	{ stack_segment, xen_stack_segment, false },
+	{ general_protection, xen_general_protection, false },
+	{ spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
+	{ coprocessor_error, xen_coprocessor_error, false },
+	{ alignment_check, xen_alignment_check, false },
+	{ simd_coprocessor_error, xen_simd_coprocessor_error, false },
+#ifdef CONFIG_TRACING
+	{ trace_page_fault, xen_trace_page_fault, false },
+#endif
+};
+
+static bool get_trap_addr(unsigned long *addr, unsigned int ist)
+{
+	unsigned int nr;
+	bool ist_okay = false;
+
+	/*
+	 * Replace trap handler addresses by Xen specific ones.
+	 * Check for known traps using IST and whitelist them.
+	 * The debugger ones are the only ones we care about.
+	 * Xen will handle faults like double_fault, * so we should never see
+	 * them.  Warn if there's an unexpected IST-using fault handler.
+	 */
+	for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++)
+		if (*addr == (unsigned long)trap_array[nr].orig) {
+			*addr = (unsigned long)trap_array[nr].xen;
+			ist_okay = trap_array[nr].ist_okay;
+			break;
+		}
+
+	if (WARN_ON(ist != 0 && !ist_okay))
+		return false;
+
+	return true;
+}
+#endif
+
 static int cvt_gate_to_trap(int vector, const gate_desc *val,
 			    struct trap_info *info)
 {
@@ -598,40 +660,8 @@  static int cvt_gate_to_trap(int vector,
 
 	addr = gate_offset(val);
 #ifdef CONFIG_X86_64
-	/*
-	 * Look for known traps using IST, and substitute them
-	 * appropriately.  The debugger ones are the only ones we care
-	 * about.  Xen will handle faults like double_fault,
-	 * so we should never see them.  Warn if
-	 * there's an unexpected IST-using fault handler.
-	 */
-	if (addr == (unsigned long)debug)
-		addr = (unsigned long)xen_debug;
-	else if (addr == (unsigned long)int3)
-		addr = (unsigned long)xen_int3;
-	else if (addr == (unsigned long)stack_segment)
-		addr = (unsigned long)xen_stack_segment;
-	else if (addr == (unsigned long)double_fault) {
-		/* Don't need to handle these */
+	if (!get_trap_addr(&addr, val->bits.ist))
 		return 0;
-#ifdef CONFIG_X86_MCE
-	} else if (addr == (unsigned long)machine_check) {
-		/*
-		 * when xen hypervisor inject vMCE to guest,
-		 * use native mce handler to handle it
-		 */
-		;
-#endif
-	} else if (addr == (unsigned long)nmi)
-		/*
-		 * Use the native version as well.
-		 */
-		;
-	else {
-		/* Some other trap using IST? */
-		if (WARN_ON(val->bits.ist != 0))
-			return 0;
-	}
 #endif	/* CONFIG_X86_64 */
 	info->address = addr;
 
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -123,9 +123,6 @@  static const struct pv_irq_ops xen_irq_o
 
 	.safe_halt = xen_safe_halt,
 	.halt = xen_halt,
-#ifdef CONFIG_X86_64
-	.adjust_exception_frame = xen_adjust_exception_frame,
-#endif
 };
 
 void __init xen_init_irq_ops(void)
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -138,7 +138,6 @@  static inline void __init xen_efi_init(v
 __visible void xen_iret(void);
 __visible void xen_sysret32(void);
 __visible void xen_sysret64(void);
-__visible void xen_adjust_exception_frame(void);
 
 extern int xen_panic_handler_init(void);