linux/arch/x86/xen/xen-head.S
Mukesh Rathor 4e903a20da 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 <mukesh.rathor@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2014-01-06 10:44:24 -05:00

131 lines
3.9 KiB
ArmAsm

/* Xen-specific pieces of head.S, intended to be included in the right
place in head.S */
#ifdef CONFIG_XEN
#include <linux/elfnote.h>
#include <linux/init.h>
#include <asm/boot.h>
#include <asm/asm.h>
#include <asm/page_types.h>
#include <xen/interface/elfnote.h>
#include <xen/interface/features.h>
#include <asm/xen/interface.h>
#ifdef CONFIG_XEN_PVH
#define PVH_FEATURES_STR "|writable_descriptor_tables|auto_translated_physmap|supervisor_mode_kernel"
/* Note the lack of 'hvm_callback_vector'. Older hypervisor will
* balk at this being part of XEN_ELFNOTE_FEATURES, so we put it in
* XEN_ELFNOTE_SUPPORTED_FEATURES which older hypervisors will ignore.
*/
#define PVH_FEATURES ((1 << XENFEAT_writable_page_tables) | \
(1 << XENFEAT_auto_translated_physmap) | \
(1 << XENFEAT_supervisor_mode_kernel) | \
(1 << XENFEAT_hvm_callback_vector))
/* The XENFEAT_writable_page_tables is not stricly neccessary as we set that
* up regardless whether this CONFIG option is enabled or not, but it
* clarifies what the right flags need to be.
*/
#else
#define PVH_FEATURES_STR ""
#define PVH_FEATURES (0)
#endif
__INIT
ENTRY(startup_xen)
cld
#ifdef CONFIG_X86_32
mov %esi,xen_start_info
mov $init_thread_union+THREAD_SIZE,%esp
#else
mov %rsi,xen_start_info
mov $init_thread_union+THREAD_SIZE,%rsp
#endif
jmp xen_start_kernel
__FINIT
.pushsection .text
.balign PAGE_SIZE
ENTRY(hypercall_page)
#define NEXT_HYPERCALL(x) \
ENTRY(xen_hypercall_##x) \
.skip 32
NEXT_HYPERCALL(set_trap_table)
NEXT_HYPERCALL(mmu_update)
NEXT_HYPERCALL(set_gdt)
NEXT_HYPERCALL(stack_switch)
NEXT_HYPERCALL(set_callbacks)
NEXT_HYPERCALL(fpu_taskswitch)
NEXT_HYPERCALL(sched_op_compat)
NEXT_HYPERCALL(platform_op)
NEXT_HYPERCALL(set_debugreg)
NEXT_HYPERCALL(get_debugreg)
NEXT_HYPERCALL(update_descriptor)
NEXT_HYPERCALL(ni)
NEXT_HYPERCALL(memory_op)
NEXT_HYPERCALL(multicall)
NEXT_HYPERCALL(update_va_mapping)
NEXT_HYPERCALL(set_timer_op)
NEXT_HYPERCALL(event_channel_op_compat)
NEXT_HYPERCALL(xen_version)
NEXT_HYPERCALL(console_io)
NEXT_HYPERCALL(physdev_op_compat)
NEXT_HYPERCALL(grant_table_op)
NEXT_HYPERCALL(vm_assist)
NEXT_HYPERCALL(update_va_mapping_otherdomain)
NEXT_HYPERCALL(iret)
NEXT_HYPERCALL(vcpu_op)
NEXT_HYPERCALL(set_segment_base)
NEXT_HYPERCALL(mmuext_op)
NEXT_HYPERCALL(xsm_op)
NEXT_HYPERCALL(nmi_op)
NEXT_HYPERCALL(sched_op)
NEXT_HYPERCALL(callback_op)
NEXT_HYPERCALL(xenoprof_op)
NEXT_HYPERCALL(event_channel_op)
NEXT_HYPERCALL(physdev_op)
NEXT_HYPERCALL(hvm_op)
NEXT_HYPERCALL(sysctl)
NEXT_HYPERCALL(domctl)
NEXT_HYPERCALL(kexec_op)
NEXT_HYPERCALL(tmem_op) /* 38 */
ENTRY(xen_hypercall_rsvr)
.skip 320
NEXT_HYPERCALL(mca) /* 48 */
NEXT_HYPERCALL(arch_1)
NEXT_HYPERCALL(arch_2)
NEXT_HYPERCALL(arch_3)
NEXT_HYPERCALL(arch_4)
NEXT_HYPERCALL(arch_5)
NEXT_HYPERCALL(arch_6)
.balign PAGE_SIZE
.popsection
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS, .asciz "linux")
ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION, .asciz "2.6")
ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION, .asciz "xen-3.0")
#ifdef CONFIG_X86_32
ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __PAGE_OFFSET)
#else
ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE, _ASM_PTR __START_KERNEL_map)
#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, .ascii "!writable_page_tables|pae_pgdir_above_4gb"; .asciz PVH_FEATURES_STR)
ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long (PVH_FEATURES) |
(1 << XENFEAT_writable_page_tables) |
(1 << XENFEAT_dom0))
ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE, .asciz "yes")
ELFNOTE(Xen, XEN_ELFNOTE_LOADER, .asciz "generic")
ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW, _ASM_PTR __HYPERVISOR_VIRT_START)
ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET, _ASM_PTR 0)
#endif /*CONFIG_XEN */