From 4e903a20da51ed2329c1b9c182dba74f47ac2ca8 Mon Sep 17 00:00:00 2001 From: Mukesh Rathor Date: Tue, 31 Dec 2013 11:16:25 -0500 Subject: xen/pvh: Support ParaVirtualized Hardware extensions (v3). PVH allows PV linux guest to utilize hardware extended capabilities, such as running MMU updates in a HVM container. The Xen side defines PVH as (from docs/misc/pvh-readme.txt, with modifications): "* the guest uses auto translate: - p2m is managed by Xen - pagetables are owned by the guest - mmu_update hypercall not available * it uses event callback and not vlapic emulation, * IDT is native, so set_trap_table hcall is also N/A for a PVH guest. For a full list of hcalls supported for PVH, see pvh_hypercall64_table in arch/x86/hvm/hvm.c in xen. From the ABI prespective, it's mostly a PV guest with auto translate, although it does use hvm_op for setting callback vector." Use .ascii and .asciz to define xen feature string. Note, the PVH string must be in a single line (not multiple lines with \) to keep the assembler from putting null char after each string before \. This patch allows it to be configured and enabled. We also use introduce the 'XEN_ELFNOTE_SUPPORTED_FEATURES' ELF note to tell the hypervisor that 'hvm_callback_vector' is what the kernel needs. We can not put it in 'XEN_ELFNOTE_FEATURES' as older hypervisor parse fields they don't understand as errors and refuse to load the kernel. This work-around fixes the problem. Signed-off-by: Mukesh Rathor Signed-off-by: Konrad Rzeszutek Wilk Acked-by: Stefano Stabellini --- include/xen/interface/elfnote.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/xen/interface') diff --git a/include/xen/interface/elfnote.h b/include/xen/interface/elfnote.h index 0360b15f4883..6f4eae328ca7 100644 --- a/include/xen/interface/elfnote.h +++ b/include/xen/interface/elfnote.h @@ -140,6 +140,19 @@ */ #define XEN_ELFNOTE_SUSPEND_CANCEL 14 +/* + * The features supported by this kernel (numeric). + * + * Other than XEN_ELFNOTE_FEATURES on pre-4.2 Xen, this note allows a + * kernel to specify support for features that older hypervisors don't + * know about. The set of features 4.2 and newer hypervisors will + * consider supported by the kernel is the combination of the sets + * specified through this and the string note. + * + * LEGACY: FEATURES + */ +#define XEN_ELFNOTE_SUPPORTED_FEATURES 17 + #endif /* __XEN_PUBLIC_ELFNOTE_H__ */ /* -- cgit v1.2.2