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Message-ID: <20121019130739.GF26830@phenom.dumpdata.com>
Date: Fri, 19 Oct 2012 09:07:39 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Mukesh Rathor <mukesh.rathor@...cle.com>
Cc: "Xen-devel@...ts.xensource.com" <Xen-devel@...ts.xensource.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 1/6]: PVH: basic and header changes, elfnote changes,
...
On Wed, Oct 17, 2012 at 05:26:42PM -0700, Mukesh Rathor wrote:
> [PATCH 1/6] PVH: is a PV linux guest that has extended capabilities. 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.
Usually one splits that description. So you have:
(for title)
"xen/pvh: Introduce ParaVirtualized Hardware support."
And then in the body do (and split it in 80 lines for
easier readability):
ParaVirtualized Hardware (PVH) support allows a PV linux guest that has extended capabilities.
[Q:Like what kind of extended capabilities? Can you explain
what they are?]
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.
[Q: You should explain why. There is nothing in this description
saying why we do not need the PV MMU anymore]
[note: the verb tense is wrong since I meshed your description
with mine, so it would have to be fixed]
>
> Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> ---
> 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 d8e33a9..425911f 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. */
> unsigned long 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 9ce788d..3b9d5b6 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -258,6 +258,16 @@ struct physdev_pci_device {
> uint8_t devfn;
> };
>
> +#define PHYSDEVOP_pvh_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 **
> --
> 1.7.2.3
--
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