Re: [PATCH 1/6] xen: balloon: allow PVMMU interfaces to be compiledout

From: Stefano Stabellini
Date: Thu Oct 18 2012 - 09:12:00 EST


On Wed, 17 Oct 2012, Ian Campbell wrote:
> The ARM platform has no concept of PVMMU and therefor no
> HYPERVISOR_update_va_mapping et al. Allow this code to be compiled out
> when not required.
>
> In some similar situations (e.g. P2M) we have defined dummy functions
> to avoid this, however I think we can/should draw the line at dummying
> out actual hypercalls.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

It is OK for me


> arch/x86/xen/Kconfig | 1 +
> drivers/xen/Kconfig | 3 +++
> drivers/xen/balloon.c | 4 ++++
> 3 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index 9323b8c..6d101a1 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -6,6 +6,7 @@ config XEN
> bool "Xen guest support"
> select PARAVIRT
> select PARAVIRT_CLOCK
> + select XEN_HAVE_PVMMU
> depends on X86_64 || (X86_32 && X86_PAE && !X86_VISWS)
> depends on X86_CMPXCHG && X86_TSC
> help
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index d4dffcd..9c00652 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -204,4 +204,7 @@ config XEN_MCE_LOG
> Allow kernel fetching MCE error from Xen platform and
> converting it into Linux mcelog format for mcelog tools
>
> +config XEN_HAVE_PVMMU
> + bool
> +
> endmenu
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index db3aa34..92449a0 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -360,6 +360,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
> if (!xen_feature(XENFEAT_auto_translated_physmap))
> set_phys_to_machine(pfn, frame_list[i]);
>
> +#ifdef CONFIG_XEN_HAVE_PVMMU
> /* Link back into the page tables if not highmem. */
> if (xen_pv_domain() && !PageHighMem(page) &&
> !xen_feature(XENFEAT_auto_translated_physmap)) {
> @@ -371,6 +372,7 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
> 0);
> BUG_ON(ret);
> }
> +#endif
>
> /* Relinquish the page back to the allocator. */
> ClearPageReserved(page);
> @@ -419,6 +421,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
>
> scrub_page(page);
>
> +#ifdef CONFIG_XEN_HAVE_PVMMU
> if (xen_pv_domain() && !PageHighMem(page)) {
> if (!xen_feature(XENFEAT_auto_translated_physmap)) {
> ret = HYPERVISOR_update_va_mapping(
> @@ -427,6 +430,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
> BUG_ON(ret);
> }
> }
> +#endif
> }
>
> /* Ensure that ballooned highmem pages don't have kmaps. */
> --
> 1.7.2.5
>
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