[PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Lai Jiangshan]

From: Lai Jiangshan <laijs@linux.alibaba.com>

There is no any functionality change intended.  Just rename it and
move it to arch/x86/kernel/nmi.c so that we can resue it later in
next patch for early NMI and kvm.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: kvm@vger.kernel.org
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
 arch/x86/include/asm/idtentry.h | 2 +-
 arch/x86/kernel/nmi.c           | 8 ++++++++
 arch/x86/xen/enlighten_pv.c     | 9 +++------
 arch/x86/xen/xen-asm.S          | 2 +-
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index e35e342673c7..5b11d2ddbb5c 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -590,7 +590,7 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_MC,	xenpv_exc_machine_check);
 /* NMI */
 DECLARE_IDTENTRY_NMI(X86_TRAP_NMI,	exc_nmi);
 #ifdef CONFIG_XEN_PV
-DECLARE_IDTENTRY_RAW(X86_TRAP_NMI,	xenpv_exc_nmi);
+DECLARE_IDTENTRY_RAW(X86_TRAP_NMI,	noist_exc_nmi);
 #endif
 
 /* #DB */
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index bf250a339655..2b907a76d0a1 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -524,6 +524,14 @@ DEFINE_IDTENTRY_RAW(exc_nmi)
 		mds_user_clear_cpu_buffers();
 }
 
+#ifdef CONFIG_XEN_PV
+DEFINE_IDTENTRY_RAW(noist_exc_nmi)
+{
+	/* On Xen PV, NMI doesn't use IST.  The C part is the same as native. */
+	exc_nmi(regs);
+}
+#endif
+
 void stop_nmi(void)
 {
 	ignore_nmis++;
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 4f18cd9eacd8..5efbdb0905b7 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -565,12 +565,6 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
 
 void noist_exc_debug(struct pt_regs *regs);
 
-DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
-{
-	/* On Xen PV, NMI doesn't use IST.  The C part is the same as native. */
-	exc_nmi(regs);
-}
-
 DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
 {
 	/* On Xen PV, DF doesn't use IST.  The C part is the same as native. */
@@ -626,6 +620,9 @@ struct trap_array_entry {
 	.xen		= xen_asm_xenpv_##func,		\
 	.ist_okay	= ist_ok }
 
+/* Alias to make TRAP_ENTRY_REDIR() happy for nmi */
+#define xen_asm_xenpv_exc_nmi	xen_asm_noist_exc_nmi
+
 static struct trap_array_entry trap_array[] = {
 	TRAP_ENTRY_REDIR(exc_debug,			true  ),
 	TRAP_ENTRY_REDIR(exc_double_fault,		true  ),
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 1e626444712b..12e7cbbb2a8d 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -130,7 +130,7 @@ _ASM_NOKPROBE(xen_\name)
 xen_pv_trap asm_exc_divide_error
 xen_pv_trap asm_xenpv_exc_debug
 xen_pv_trap asm_exc_int3
-xen_pv_trap asm_xenpv_exc_nmi
+xen_pv_trap asm_noist_exc_nmi
 xen_pv_trap asm_exc_overflow
 xen_pv_trap asm_exc_bounds
 xen_pv_trap asm_exc_invalid_op
-- 
2.19.1.6.gb485710b

Re: [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Steven Rostedt]

On Tue, 27 Apr 2021 07:09:46 +0800
Lai Jiangshan <jiangshanlai@gmail.com> wrote:

> From: Lai Jiangshan <laijs@linux.alibaba.com>
> 
> There is no any functionality change intended.  Just rename it and
> move it to arch/x86/kernel/nmi.c so that we can resue it later in
> next patch for early NMI and kvm.

Nit, but in change logs, please avoid stating "next patch" as searching git
history (via git blame or whatever) there is no such thing as "next patch".

Just state: "so that we can reuse it for early NMI and KVM."

I also just noticed the typo in "resue". Or maybe both NMI and KVM should
be sued again ;-)

-- Steve

Re: [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Paolo Bonzini]

On 28/04/21 23:27, Steven Rostedt wrote:
> On Tue, 27 Apr 2021 07:09:46 +0800
> Lai Jiangshan <jiangshanlai@gmail.com> wrote:
> 
>> From: Lai Jiangshan <laijs@linux.alibaba.com>
>>
>> There is no any functionality change intended.  Just rename it and
>> move it to arch/x86/kernel/nmi.c so that we can resue it later in
>> next patch for early NMI and kvm.
> 
> Nit, but in change logs, please avoid stating "next patch" as searching git
> history (via git blame or whatever) there is no such thing as "next patch".

Interesting, I use next patch(es) relatively often, though you're right 
that something like "in preparation for" works just as well.  Yes, it's 
the previous in "git log", but you get what it's meant in practice. :)

Paolo

> Just state: "so that we can reuse it for early NMI and KVM."
> 
> I also just noticed the typo in "resue". Or maybe both NMI and KVM should
> be sued again ;-)
> 
> -- Steve
> 

Re: [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Steven Rostedt]

On Fri, 30 Apr 2021 09:15:51 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> > Nit, but in change logs, please avoid stating "next patch" as searching git
> > history (via git blame or whatever) there is no such thing as "next patch".  
> 
> Interesting, I use next patch(es) relatively often, though you're right 
> that something like "in preparation for" works just as well.  Yes, it's 
> the previous in "git log", but you get what it's meant in practice. :)

It's not always the previous in a git log. Git log sorts by time, and
if an unrelated commit was created in between those two patches, it
will be in between them.

-- Steve

Re: [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Thomas Gleixner]

On Tue, Apr 27 2021 at 07:09, Lai Jiangshan wrote:
> From: Lai Jiangshan <laijs@linux.alibaba.com>
>
> There is no any functionality change intended.  Just rename it and
> move it to arch/x86/kernel/nmi.c so that we can resue it later in
> next patch for early NMI and kvm.

'Reuse it later' is not really a proper explanation why this change it
necessary.

Also this can be simplified by using aliasing which keeps the name
spaces intact.

Thanks,

        tglx
---       

--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -135,6 +135,9 @@ static __always_inline void __##func(str
 #define DEFINE_IDTENTRY_RAW(func)					\
 __visible noinstr void func(struct pt_regs *regs)
 
+#define DEFINE_IDTENTRY_RAW_ALIAS(alias, func)				\
+__visible noinstr void func(struct pt_regs *regs) __alias(alias)
+
 /**
  * DECLARE_IDTENTRY_RAW_ERRORCODE - Declare functions for raw IDT entry points
  *				    Error code pushed by hardware
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -524,6 +524,8 @@ DEFINE_IDTENTRY_RAW(exc_nmi)
 		mds_user_clear_cpu_buffers();
 }
 
+DEFINE_IDTENTRY_RAW_ALIAS(exc_nmi, xenpv_exc_nmi);
+
 void stop_nmi(void)
 {
 	ignore_nmis++;
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -565,12 +565,6 @@ static void xen_write_ldt_entry(struct d
 
 void noist_exc_debug(struct pt_regs *regs);
 
-DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
-{
-	/* On Xen PV, NMI doesn't use IST.  The C part is the same as native. */
-	exc_nmi(regs);
-}
-
 DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
 {
 	/* On Xen PV, DF doesn't use IST.  The C part is the same as native. */

Re: [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Thomas Gleixner]

On Mon, May 03 2021 at 21:05, Thomas Gleixner wrote:

> On Tue, Apr 27 2021 at 07:09, Lai Jiangshan wrote:
>> From: Lai Jiangshan <laijs@linux.alibaba.com>
>>
>> There is no any functionality change intended.  Just rename it and
>> move it to arch/x86/kernel/nmi.c so that we can resue it later in
>> next patch for early NMI and kvm.
>
> 'Reuse it later' is not really a proper explanation why this change it
> necessary.
>
> Also this can be simplified by using aliasing which keeps the name
> spaces intact.

Aside of that this is not required to be part of a fixes series which
needs to be backported.

Thanks,

        tglx

Re: [PATCH 1/4] x86/xen/entry: Rename xenpv_exc_nmi to noist_exc_nmi

[Juergen Gross]

[-- Attachment #1.1.1: Type: text/plain, Size: 969 bytes --]

On 27.04.21 01:09, Lai Jiangshan wrote:
> From: Lai Jiangshan <laijs@linux.alibaba.com>
> 
> There is no any functionality change intended.  Just rename it and
> move it to arch/x86/kernel/nmi.c so that we can resue it later in
> next patch for early NMI and kvm.
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Sean Christopherson <seanjc@google.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
> Cc: Wanpeng Li <wanpengli@tencent.com>
> Cc: Jim Mattson <jmattson@google.com>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: kvm@vger.kernel.org
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Uros Bizjak <ubizjak@gmail.com>
> Cc: Maxim Levitsky <mlevitsk@redhat.com>
> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>

Acked-by: Juergen Gross <jgross@suse.com>


Juergen

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