Re: [PATCH V10 01/14] xen/pvh: Support ParaVirtualized Hardware extensions.

From: David Vrabel
Date: Fri Dec 13 2013 - 05:44:39 EST


On 13/12/13 02:10, 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).
[...]
> --- a/arch/x86/include/asm/xen/page.h
> +++ b/arch/x86/include/asm/xen/page.h
> @@ -168,6 +168,9 @@ 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;

This does the mfn_to_pfn() call first and then ignores the result.

> 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 1a3c765..4d890c3 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -51,3 +51,13 @@ 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

Drop EXPERIMENTAL here (not in the follow up patch).

> + default n

default y or don't provide this as a user selectable choice.

> 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,

Not clear how this can be part of the first patch. A guest with only
this patch cannot actually work in PVH mode, right?

> diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
> index 2ecfe4f..a122164 100644
> --- a/include/xen/interface/memory.h
> +++ b/include/xen/interface/memory.h
> @@ -175,7 +175,10 @@ struct xen_add_to_physmap {
> uint16_t size;
>
> /* Source mapping space. */
> - unsigned int space;
> + uint16_t space;
> + domid_t foreign_domid; /* IFF XENMAPSPACE_gmfn_foreign */
> +
> +#define XENMAPIDX_grant_table_status 0x80000000

What's this change? It doesn't match the hypervisor.

> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -291,6 +291,16 @@ 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 */
> +
> +};
> +

Not provided by the hypervisor.

David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/