Re: [PATCH 1/6] xen/pvh: Support ParaVirtualized Hardwareextensions.

[Stefano Stabellini]

On Sat, 20 Oct 2012, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> 
> PVH allows PV linux guest to utilize hardware extended capabilities, such
> as running MMU updates in a HVM container.
> 
> This patch allows it to be configured and enabled. Also, basic header file
> changes to add new subcalls to physmap hypercall.
> 
> Lastly, mfn_to_local_pfn must return mfn for paging mode translate
> (since we let the hypervisor - or CPU - do them for us).
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>


Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

>  arch/x86/include/asm/xen/page.h |    3 +++
>  arch/x86/xen/Kconfig            |   10 ++++++++++
>  arch/x86/xen/xen-head.S         |   11 ++++++++++-
>  include/xen/interface/memory.h  |   24 +++++++++++++++++++++++-
>  include/xen/interface/physdev.h |   10 ++++++++++
>  5 files changed, 56 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
> index 472b9b7..6af440d 100644
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -159,6 +159,9 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine)
>  static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
>  {
>  	unsigned long pfn = mfn_to_pfn(mfn);
> +
> +	if (xen_feature(XENFEAT_auto_translated_physmap))
> +		return mfn;
>  	if (get_phys_to_machine(pfn) != mfn)
>  		return -1; /* force !pfn_valid() */
>  	return pfn;
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index fdce49c..822c5a0 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -50,3 +50,13 @@ config XEN_DEBUG_FS
>  	  Enable statistics output and various tuning options in debugfs.
>  	  Enabling this option may incur a significant performance overhead.
>  
> +config XEN_X86_PVH
> +	bool "Support for running as a PVH guest (EXPERIMENTAL)"
> +	depends on X86_64 && XEN && EXPERIMENTAL
> +	default n
> +	help
> +	   This option enables support for running as a PVH guest (PV guest
> +	   using hardware extensions) under a suitably capable hypervisor.
> +	   This option is EXPERIMENTAL because the hypervisor interfaces
> +	   which it uses are not yet considered stable therefore backwards and
> +	   forwards compatibility is not yet guaranteed.  If unsure, say N.
> diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
> index 7faed58..1a6bca1 100644
> --- a/arch/x86/xen/xen-head.S
> +++ b/arch/x86/xen/xen-head.S
> @@ -13,6 +13,15 @@
>  #include <xen/interface/elfnote.h>
>  #include <asm/xen/interface.h>
>  
> +#ifdef CONFIG_XEN_X86_PVH
> +#define FEATURES_PVH "|writable_descriptor_tables" \
> +		     "|auto_translated_physmap" \
> +		     "|supervisor_mode_kernel" \
> +		     "|hvm_callback_vector"
> +#else
> +#define FEATURES_PVH /* Not supported */
> +#endif
> +
>  	__INIT
>  ENTRY(startup_xen)
>  	cld
> @@ -95,7 +104,7 @@ NEXT_HYPERCALL(arch_6)
>  #endif
>  	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
>  	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
> -	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz "!writable_page_tables|pae_pgdir_above_4gb")
> +	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz "!writable_page_tables|pae_pgdir_above_4gb"FEATURES_PVH)
>  	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
>  	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
>  	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
> diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
> index b66d04c..8beebdb 100644
> --- a/include/xen/interface/memory.h
> +++ b/include/xen/interface/memory.h
> @@ -169,7 +169,13 @@ struct xen_add_to_physmap {
>      /* Source mapping space. */
>  #define XENMAPSPACE_shared_info 0 /* shared info page */
>  #define XENMAPSPACE_grant_table 1 /* grant table page */
> -    unsigned int space;
> +#define XENMAPSPACE_gmfn        2 /* GMFN */
> +#define XENMAPSPACE_gmfn_range  3 /* GMFN range */
> +#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another guest */
> +    uint16_t space;
> +    domid_t foreign_domid;         /* IFF XENMAPSPACE_gmfn_foreign */
> +
> +#define XENMAPIDX_grant_table_status 0x80000000
>  
>      /* Index into source mapping space. */
>      xen_ulong_t idx;
> @@ -237,4 +243,20 @@ DEFINE_GUEST_HANDLE_STRUCT(xen_memory_map);
>   * during a driver critical region.
>   */
>  extern spinlock_t xen_reservation_lock;
> +
> +/*
> + * Unmaps the page appearing at a particular GPFN from the specified guest's
> + * pseudophysical address space.
> + * arg == addr of xen_remove_from_physmap_t.
> + */
> +#define XENMEM_remove_from_physmap      15
> +struct xen_remove_from_physmap {
> +    /* Which domain to change the mapping for. */
> +    domid_t domid;
> +
> +    /* GPFN of the current mapping of the page. */
> +    xen_pfn_t gpfn;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);
> +
>  #endif /* __XEN_PUBLIC_MEMORY_H__ */
> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index 1844d31..83050d3 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -274,6 +274,16 @@ struct physdev_dbgp_op {
>      } u;
>  };
>  
> +#define PHYSDEVOP_map_iomem        30
> +struct physdev_map_iomem {
> +    /* IN */
> +    uint64_t first_gfn;
> +    uint64_t first_mfn;
> +    uint32_t nr_mfns;
> +    uint32_t add_mapping; /* 1 == add mapping;  0 == unmap */
> +
> +};
> +
>  /*
>   * Notify that some PIRQ-bound event channels have been unmasked.
>   * ** This command is obsolete since interface version 0x00030202 and is **
> -- 
> 1.7.7.6
> 
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