[PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS

Penny Zheng posted 24 patches 3 weeks, 1 day ago
There is a newer version of this series
[PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS
Posted by Penny Zheng 3 weeks, 1 day ago
Function arch_do_domctl() is responsible for arch-specific domctl-op,
and shall be wrapped with CONFIG_MGMT_HYPERCALLS
We focus on x86 implementation here only. Tracking its calling chain and the
following functions shall be wrapped with CONFIG_MGMT_HYPERCALLS too.
Otherwise they will all become unreachable when MGMT_HYPERCALLS=n, and hence
violating Misra Rule 2.1.
- hvm_acpi_power_button
- hvm_acpi_sleep_button
- hvm_debug_op
- make P2M_AUDIT depend on CONFIG_MGMT_HYPERCALLS
- make PG_log_dirty depend on CONFIG_MGMT_HYPERCALLS
- make cpuid.o/policy.o/msr.o depend on CONFIG_MGMT_HYPERCALLS
- make HAS_SOFT_RESET depend on CONFIG_MGMT_HYPERCALLS
- make VMTRACE depend on CONFIG_MGMT_HYPERCALLS
- paging_domctl_cont
We put the guardian in Makefile for the arch-specific domctl.o compilation.

Signed-off-by: Penny Zheng <Penny.Zheng@amd.com>
---
v1 -> v2:
- split out xsm parts
- adapt to changes of "unify DOMCTL to MGMT_HYPERCALLS"
- wrap default-case and arch_get_domain_info() transiently
---
v2 -> v3:
- add missing guardian in arm/Makefile
- cover RTIT_CTL{,STATUS}_MASK #define-s
- add missing guardian for .vmtrace_output_position
- guard the whole static inline function
- address "violating Misra rule 2.1" in commit message
- remove transient wrapping around default-case and arch_get_domain_info()
---
v3 -> v4:
- make HAS_SOFT_RESET depend on CONFIG_MGMT_HYPERCALLS
- make VMTRACE depend on CONFIG_MGMT_HYPERCALLS
- seperate depends on condition for future convenience
- split arch-specific domctl-op into x86 and arm
---
 xen/Kconfig.debug                 | 1 +
 xen/arch/x86/Kconfig              | 2 +-
 xen/arch/x86/Makefile             | 2 +-
 xen/arch/x86/hvm/Kconfig          | 1 +
 xen/arch/x86/hvm/hvm.c            | 2 ++
 xen/arch/x86/hvm/pmtimer.c        | 2 ++
 xen/arch/x86/include/asm/p2m.h    | 2 +-
 xen/arch/x86/include/asm/paging.h | 2 +-
 xen/include/hypercall-defs.c      | 4 +++-
 xen/lib/x86/Makefile              | 6 +++---
 10 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug
index a69615cd63..c078c6bf2e 100644
--- a/xen/Kconfig.debug
+++ b/xen/Kconfig.debug
@@ -15,6 +15,7 @@ if DEBUG || EXPERT
 
 config GDBSX
 	bool "Guest debugging with gdbsx"
+	depends on MGMT_HYPERCALLS
 	depends on X86
 	default y
 	help
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 8368c6ecf0..d49681beed 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -29,7 +29,7 @@ config X86
 	select HAS_PCI_MSI
 	select HAS_PIRQ
 	select HAS_SCHED_GRANULARITY
-	imply HAS_SOFT_RESET
+	select HAS_SOFT_RESET if MGMT_HYPERCALLS
 	select HAS_UBSAN
 	select HAS_VMAP
 	select HAS_VPCI if HVM
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index d21fdd49df..006a6e56d3 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -79,7 +79,7 @@ obj-$(CONFIG_VM_EVENT) += vm_event.o
 obj-y += xstate.o
 
 ifneq ($(CONFIG_PV_SHIM_EXCLUSIVE),y)
-obj-y += domctl.o
+obj-$(CONFIG_MGMT_HYPERCALLS) += domctl.o
 obj-y += platform_hypercall.o
 obj-$(CONFIG_COMPAT) += x86_64/platform_hypercall.o
 endif
diff --git a/xen/arch/x86/hvm/Kconfig b/xen/arch/x86/hvm/Kconfig
index d540c0ebf3..52b22e5d17 100644
--- a/xen/arch/x86/hvm/Kconfig
+++ b/xen/arch/x86/hvm/Kconfig
@@ -37,6 +37,7 @@ config INTEL_VMX
 config VMTRACE
 	bool "HW VM tracing support"
 	depends on INTEL_VMX
+	depends on MGMT_HYPERCALLS
 	default y
 	help
 	  Enables HW VM tracing support which allows to configure HW processor
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index d03f563d76..b03f7dfcf6 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -5204,6 +5204,7 @@ long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
     return rc;
 }
 
+#ifdef CONFIG_MGMT_HYPERCALLS
 int hvm_debug_op(struct vcpu *v, int32_t op)
 {
     int rc = 0;
@@ -5246,6 +5247,7 @@ int hvm_debug_op(struct vcpu *v, int32_t op)
 
     return rc;
 }
+#endif /* CONFIG_MGMT_HYPERCALLS */
 
 #ifdef CONFIG_VM_EVENT
 void hvm_toggle_singlestep(struct vcpu *v)
diff --git a/xen/arch/x86/hvm/pmtimer.c b/xen/arch/x86/hvm/pmtimer.c
index 87a7a01c9f..f080f7561d 100644
--- a/xen/arch/x86/hvm/pmtimer.c
+++ b/xen/arch/x86/hvm/pmtimer.c
@@ -56,6 +56,7 @@ static void pmt_update_sci(PMTState *s)
         hvm_isa_irq_deassert(s->vcpu->domain, SCI_IRQ);
 }
 
+#ifdef CONFIG_MGMT_HYPERCALLS
 void hvm_acpi_power_button(struct domain *d)
 {
     PMTState *s = &d->arch.hvm.pl_time->vpmt;
@@ -81,6 +82,7 @@ void hvm_acpi_sleep_button(struct domain *d)
     pmt_update_sci(s);
     spin_unlock(&s->lock);
 }
+#endif /* CONFIG_MGMT_HYPERCALLS */
 
 /* Set the correct value in the timer, accounting for time elapsed
  * since the last time we did that. */
diff --git a/xen/arch/x86/include/asm/p2m.h b/xen/arch/x86/include/asm/p2m.h
index 9016e88411..3574e2eecd 100644
--- a/xen/arch/x86/include/asm/p2m.h
+++ b/xen/arch/x86/include/asm/p2m.h
@@ -20,7 +20,7 @@
 #include <asm/page.h>    /* for pagetable_t */
 
 /* Debugging and auditing of the P2M code? */
-#if !defined(NDEBUG) && defined(CONFIG_HVM)
+#if !defined(NDEBUG) && defined(CONFIG_HVM) && defined(CONFIG_MGMT_HYPERCALLS)
 #define P2M_AUDIT     1
 #else
 #define P2M_AUDIT     0
diff --git a/xen/arch/x86/include/asm/paging.h b/xen/arch/x86/include/asm/paging.h
index 0c06b0a7a8..ba5ba7324e 100644
--- a/xen/arch/x86/include/asm/paging.h
+++ b/xen/arch/x86/include/asm/paging.h
@@ -55,7 +55,7 @@
 #define PG_translate   0
 #define PG_external    0
 #endif
-#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
+#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE) && defined(CONFIG_MGMT_HYPERCALLS)
 /* Enable log dirty mode */
 #define PG_log_dirty   (XEN_DOMCTL_SHADOW_ENABLE_LOG_DIRTY << PG_mode_shift)
 #else
diff --git a/xen/include/hypercall-defs.c b/xen/include/hypercall-defs.c
index 4840de805b..38b21dccbd 100644
--- a/xen/include/hypercall-defs.c
+++ b/xen/include/hypercall-defs.c
@@ -196,10 +196,10 @@ dm_op(domid_t domid, unsigned int nr_bufs, xen_dm_op_buf_t *bufs)
 #endif
 #ifdef CONFIG_MGMT_HYPERCALLS
 sysctl(xen_sysctl_t *u_sysctl)
-#endif
 #if defined(CONFIG_X86) && defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
 paging_domctl_cont(xen_domctl_t *u_domctl)
 #endif
+#endif
 #ifndef CONFIG_PV_SHIM_EXCLUSIVE
 domctl(xen_domctl_t *u_domctl)
 platform_op(xen_platform_op_t *u_xenpf_op)
@@ -299,7 +299,9 @@ hypfs_op                           do       do       do       do       do
 #endif
 mca                                do       do       -        -        -
 #if defined(CONFIG_X86) && defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
+#ifdef CONFIG_MGMT_HYPERCALLS
 paging_domctl_cont                 do       do       do       do       -
 #endif
+#endif
 
 #endif /* !CPPCHECK */
diff --git a/xen/lib/x86/Makefile b/xen/lib/x86/Makefile
index ac6d4369f3..124af43ea0 100644
--- a/xen/lib/x86/Makefile
+++ b/xen/lib/x86/Makefile
@@ -1,4 +1,4 @@
-obj-y += cpuid.o
+obj-$(CONFIG_MGMT_HYPERCALLS) += cpuid.o
 obj-y += cpuid-generic.o
-obj-y += msr.o
-obj-y += policy.o
+obj-$(CONFIG_MGMT_HYPERCALLS) += msr.o
+obj-$(CONFIG_MGMT_HYPERCALLS) += policy.o
-- 
2.34.1
Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS
Posted by Jan Beulich 2 weeks, 4 days ago
On 21.11.2025 11:57, Penny Zheng wrote:
> --- a/xen/arch/x86/Kconfig
> +++ b/xen/arch/x86/Kconfig
> @@ -29,7 +29,7 @@ config X86
>  	select HAS_PCI_MSI
>  	select HAS_PIRQ
>  	select HAS_SCHED_GRANULARITY
> -	imply HAS_SOFT_RESET
> +	select HAS_SOFT_RESET if MGMT_HYPERCALLS

Why would you undo an "imply", when really we should use it more? One of its
purposes is so that you can add "depends on MGMT_HYPERCALLS" there, and it
then won't be auto-enabled if that dependency isn't fulfilled.

> --- a/xen/arch/x86/include/asm/paging.h
> +++ b/xen/arch/x86/include/asm/paging.h
> @@ -55,7 +55,7 @@
>  #define PG_translate   0
>  #define PG_external    0
>  #endif
> -#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
> +#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE) && defined(CONFIG_MGMT_HYPERCALLS)

This line is too long now.

> @@ -299,7 +299,9 @@ hypfs_op                           do       do       do       do       do
>  #endif
>  mca                                do       do       -        -        -
>  #if defined(CONFIG_X86) && defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
> +#ifdef CONFIG_MGMT_HYPERCALLS

Why not combine with the existing #if?

Jan
RE: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS
Posted by Penny, Zheng 1 week, 3 days ago
[Public]

> -----Original Message-----
> From: Jan Beulich <jbeulich@suse.com>
> Sent: Wednesday, November 26, 2025 1:00 AM
> To: Penny, Zheng <penny.zheng@amd.com>
> Cc: Huang, Ray <Ray.Huang@amd.com>; grygorii_strashko@epam.com; Andrew
> Cooper <andrew.cooper3@citrix.com>; Anthony PERARD
> <anthony.perard@vates.tech>; Orzel, Michal <Michal.Orzel@amd.com>; Julien
> Grall <julien@xen.org>; Roger Pau Monné <roger.pau@citrix.com>; Stefano
> Stabellini <sstabellini@kernel.org>; Daniel P. Smith
> <dpsmith@apertussolutions.com>; xen-devel@lists.xenproject.org
> Subject: Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with
> CONFIG_MGMT_HYPERCALLS
>
> On 21.11.2025 11:57, Penny Zheng wrote:
> > --- a/xen/arch/x86/Kconfig
> > +++ b/xen/arch/x86/Kconfig
> > @@ -29,7 +29,7 @@ config X86
> >     select HAS_PCI_MSI
> >     select HAS_PIRQ
> >     select HAS_SCHED_GRANULARITY
> > -   imply HAS_SOFT_RESET
> > +   select HAS_SOFT_RESET if MGMT_HYPERCALLS
>
> Why would you undo an "imply", when really we should use it more? One of its
> purposes is so that you can add "depends on MGMT_HYPERCALLS" there, and it
> then won't be auto-enabled if that dependency isn't fulfilled.
>
> > --- a/xen/arch/x86/include/asm/paging.h
> > +++ b/xen/arch/x86/include/asm/paging.h
> > @@ -55,7 +55,7 @@
> >  #define PG_translate   0
> >  #define PG_external    0
> >  #endif
> > -#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
> > +#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
> &&
> > +defined(CONFIG_MGMT_HYPERCALLS)
>
> This line is too long now.

Hmm, how about I introduce a new Kconfig, something like:
```
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index c808c989fc..ec8f51b0b1 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -166,6 +166,9 @@ config SHADOW_PAGING
 config PAGING
        def_bool HVM || SHADOW_PAGING

+config PAGING_LOG_DIRTY
+       def_bool PAGING
+
 config BIGMEM
        bool "big memory support"
        default n
```
Then, later future dependency could be added to PAGING_LOG_DIRTY

> Jan
Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS
Posted by Jan Beulich 1 week, 2 days ago
On 04.12.2025 05:23, Penny, Zheng wrote:
> [Public]
> 
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: Wednesday, November 26, 2025 1:00 AM
>> To: Penny, Zheng <penny.zheng@amd.com>
>> Cc: Huang, Ray <Ray.Huang@amd.com>; grygorii_strashko@epam.com; Andrew
>> Cooper <andrew.cooper3@citrix.com>; Anthony PERARD
>> <anthony.perard@vates.tech>; Orzel, Michal <Michal.Orzel@amd.com>; Julien
>> Grall <julien@xen.org>; Roger Pau Monné <roger.pau@citrix.com>; Stefano
>> Stabellini <sstabellini@kernel.org>; Daniel P. Smith
>> <dpsmith@apertussolutions.com>; xen-devel@lists.xenproject.org
>> Subject: Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with
>> CONFIG_MGMT_HYPERCALLS
>>
>> On 21.11.2025 11:57, Penny Zheng wrote:
>>> --- a/xen/arch/x86/Kconfig
>>> +++ b/xen/arch/x86/Kconfig
>>> @@ -29,7 +29,7 @@ config X86
>>>     select HAS_PCI_MSI
>>>     select HAS_PIRQ
>>>     select HAS_SCHED_GRANULARITY
>>> -   imply HAS_SOFT_RESET
>>> +   select HAS_SOFT_RESET if MGMT_HYPERCALLS
>>
>> Why would you undo an "imply", when really we should use it more? One of its
>> purposes is so that you can add "depends on MGMT_HYPERCALLS" there, and it
>> then won't be auto-enabled if that dependency isn't fulfilled.
>>
>>> --- a/xen/arch/x86/include/asm/paging.h
>>> +++ b/xen/arch/x86/include/asm/paging.h
>>> @@ -55,7 +55,7 @@
>>>  #define PG_translate   0
>>>  #define PG_external    0
>>>  #endif
>>> -#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
>>> +#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
>> &&
>>> +defined(CONFIG_MGMT_HYPERCALLS)
>>
>> This line is too long now.
> 
> Hmm, how about I introduce a new Kconfig, something like:
> ```
> diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
> index c808c989fc..ec8f51b0b1 100644
> --- a/xen/arch/x86/Kconfig
> +++ b/xen/arch/x86/Kconfig
> @@ -166,6 +166,9 @@ config SHADOW_PAGING
>  config PAGING
>         def_bool HVM || SHADOW_PAGING
> 
> +config PAGING_LOG_DIRTY
> +       def_bool PAGING
> +
>  config BIGMEM
>         bool "big memory support"
>         default n
> ```
> Then, later future dependency could be added to PAGING_LOG_DIRTY

I fear I don't see how having an option merely aliasing another option
would help the line length issue. I may simply be missing some context ...

Jan

RE: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS
Posted by Penny, Zheng 1 week, 2 days ago
[Public]

> -----Original Message-----
> From: Jan Beulich <jbeulich@suse.com>
> Sent: Thursday, December 4, 2025 5:41 PM
> To: Penny, Zheng <penny.zheng@amd.com>
> Cc: Huang, Ray <Ray.Huang@amd.com>; grygorii_strashko@epam.com; Andrew
> Cooper <andrew.cooper3@citrix.com>; Anthony PERARD
> <anthony.perard@vates.tech>; Orzel, Michal <Michal.Orzel@amd.com>; Julien
> Grall <julien@xen.org>; Roger Pau Monné <roger.pau@citrix.com>; Stefano
> Stabellini <sstabellini@kernel.org>; Daniel P. Smith
> <dpsmith@apertussolutions.com>; xen-devel@lists.xenproject.org
> Subject: Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with
> CONFIG_MGMT_HYPERCALLS
>
> On 04.12.2025 05:23, Penny, Zheng wrote:
> > [Public]
> >
> >> -----Original Message-----
> >> From: Jan Beulich <jbeulich@suse.com>
> >> Sent: Wednesday, November 26, 2025 1:00 AM
> >> To: Penny, Zheng <penny.zheng@amd.com>
> >> Cc: Huang, Ray <Ray.Huang@amd.com>; grygorii_strashko@epam.com;
> >> Andrew Cooper <andrew.cooper3@citrix.com>; Anthony PERARD
> >> <anthony.perard@vates.tech>; Orzel, Michal <Michal.Orzel@amd.com>;
> >> Julien Grall <julien@xen.org>; Roger Pau Monné
> >> <roger.pau@citrix.com>; Stefano Stabellini <sstabellini@kernel.org>;
> >> Daniel P. Smith <dpsmith@apertussolutions.com>;
> >> xen-devel@lists.xenproject.org
> >> Subject: Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op
> >> with CONFIG_MGMT_HYPERCALLS
> >>
> >> On 21.11.2025 11:57, Penny Zheng wrote:
> >>> --- a/xen/arch/x86/Kconfig
> >>> +++ b/xen/arch/x86/Kconfig
> >>> @@ -29,7 +29,7 @@ config X86
> >>>     select HAS_PCI_MSI
> >>>     select HAS_PIRQ
> >>>     select HAS_SCHED_GRANULARITY
> >>> -   imply HAS_SOFT_RESET
> >>> +   select HAS_SOFT_RESET if MGMT_HYPERCALLS
> >>
> >> Why would you undo an "imply", when really we should use it more? One
> >> of its purposes is so that you can add "depends on MGMT_HYPERCALLS"
> >> there, and it then won't be auto-enabled if that dependency isn't fulfilled.
> >>
> >>> --- a/xen/arch/x86/include/asm/paging.h
> >>> +++ b/xen/arch/x86/include/asm/paging.h
> >>> @@ -55,7 +55,7 @@
> >>>  #define PG_translate   0
> >>>  #define PG_external    0
> >>>  #endif
> >>> -#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
> >>> +#if defined(CONFIG_PAGING)
> && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
> >> &&
> >>> +defined(CONFIG_MGMT_HYPERCALLS)
> >>
> >> This line is too long now.
> >
> > Hmm, how about I introduce a new Kconfig, something like:
> > ```
> > diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig index
> > c808c989fc..ec8f51b0b1 100644
> > --- a/xen/arch/x86/Kconfig
> > +++ b/xen/arch/x86/Kconfig
> > @@ -166,6 +166,9 @@ config SHADOW_PAGING  config PAGING
> >         def_bool HVM || SHADOW_PAGING
> >
> > +config PAGING_LOG_DIRTY
> > +       def_bool PAGING
> > +
> >  config BIGMEM
> >         bool "big memory support"
> >         default n
> > ```
> > Then, later future dependency could be added to PAGING_LOG_DIRTY
>
> I fear I don't see how having an option merely aliasing another option would help the
> line length issue. I may simply be missing some context ...

Later when MGMT_HYPERCCALLS kicks in, we could have to avoid overlong #ifdef:
```
#if defined(CONFIG_PAGING_LOG_DIRTY) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
#define PG_log_dirty   (XEN_DOMCTL_SHADOW_ENABLE_LOG_DIRTY << PG_mode_shift)
...
```
The addition of MGMT_HYPERCCALLS dependency could be added to PAGING_LOG_DIRTY kconfig
```
config PAGING_LOG_DIRTY
        def_bool PAGING && MGMT_HYPERCALLS
```

>
> Jan
Re: [PATCH v4 20/24] xen/x86: wrap x86-specific domctl-op with CONFIG_MGMT_HYPERCALLS
Posted by Jan Beulich 1 week, 1 day ago
On 05.12.2025 04:28, Penny, Zheng wrote:
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: Thursday, December 4, 2025 5:41 PM
>>
>> On 04.12.2025 05:23, Penny, Zheng wrote:
>>>
>>>> -----Original Message-----
>>>> From: Jan Beulich <jbeulich@suse.com>
>>>> Sent: Wednesday, November 26, 2025 1:00 AM
>>>>
>>>> On 21.11.2025 11:57, Penny Zheng wrote:
>>>>> --- a/xen/arch/x86/Kconfig
>>>>> +++ b/xen/arch/x86/Kconfig
>>>>> @@ -29,7 +29,7 @@ config X86
>>>>>     select HAS_PCI_MSI
>>>>>     select HAS_PIRQ
>>>>>     select HAS_SCHED_GRANULARITY
>>>>> -   imply HAS_SOFT_RESET
>>>>> +   select HAS_SOFT_RESET if MGMT_HYPERCALLS
>>>>
>>>> Why would you undo an "imply", when really we should use it more? One
>>>> of its purposes is so that you can add "depends on MGMT_HYPERCALLS"
>>>> there, and it then won't be auto-enabled if that dependency isn't fulfilled.
>>>>
>>>>> --- a/xen/arch/x86/include/asm/paging.h
>>>>> +++ b/xen/arch/x86/include/asm/paging.h
>>>>> @@ -55,7 +55,7 @@
>>>>>  #define PG_translate   0
>>>>>  #define PG_external    0
>>>>>  #endif
>>>>> -#if defined(CONFIG_PAGING) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
>>>>> +#if defined(CONFIG_PAGING)
>> && !defined(CONFIG_PV_SHIM_EXCLUSIVE)
>>>> &&
>>>>> +defined(CONFIG_MGMT_HYPERCALLS)
>>>>
>>>> This line is too long now.
>>>
>>> Hmm, how about I introduce a new Kconfig, something like:
>>> ```
>>> diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig index
>>> c808c989fc..ec8f51b0b1 100644
>>> --- a/xen/arch/x86/Kconfig
>>> +++ b/xen/arch/x86/Kconfig
>>> @@ -166,6 +166,9 @@ config SHADOW_PAGING  config PAGING
>>>         def_bool HVM || SHADOW_PAGING
>>>
>>> +config PAGING_LOG_DIRTY
>>> +       def_bool PAGING
>>> +
>>>  config BIGMEM
>>>         bool "big memory support"
>>>         default n
>>> ```
>>> Then, later future dependency could be added to PAGING_LOG_DIRTY
>>
>> I fear I don't see how having an option merely aliasing another option would help the
>> line length issue. I may simply be missing some context ...
> 
> Later when MGMT_HYPERCCALLS kicks in, we could have to avoid overlong #ifdef:
> ```
> #if defined(CONFIG_PAGING_LOG_DIRTY) && !defined(CONFIG_PV_SHIM_EXCLUSIVE)

Yet this is a bogus construct to have. It really means PAGING_LOG_DIRTY would
better depend on !PV_SHIM_EXCLUSIVE, except that this is precisely the
pattern we want to get rid of. At which point imo the usefulness of
PAGING_LOG_DIRTY would be somewhat limited.

Jan

> #define PG_log_dirty   (XEN_DOMCTL_SHADOW_ENABLE_LOG_DIRTY << PG_mode_shift)
> ...
> ```
> The addition of MGMT_HYPERCCALLS dependency could be added to PAGING_LOG_DIRTY kconfig
> ```
> config PAGING_LOG_DIRTY
>         def_bool PAGING && MGMT_HYPERCALLS
> ```
> 
>>
>> Jan