Because the x86_64 architecture does not enforce segment limits, Xen
cannot protect itself with them as it does in 32-bit mode.  Therefore,
to protect itself, it runs the guest kernel in ring 3.  Since it also
runs the guest userspace in ring3, the guest kernel must maintain a
second pagetable for its userspace, which does not map kernel space.
Naturally, the guest kernel pagetables map both kernel and userspace.

The userspace pagetable is attached to the corresponding kernel
pagetable via the pgd's page->private field.  It is allocated and
freed at the same time as the kernel pgd via the
paravirt_pgd_alloc/free hooks.

Fortunately, the user pagetable is almost entirely shared with the
kernel pagetable; the only difference is the pgd page itself.  set_pgd
will populate all entries in the kernel pagetable, and also set the
corresponding user pgd entry if the address is less than
STACK_TOP_MAX.

The user pagetable must be pinned and unpinned with the kernel one,
but because the pagetables are aliased, pgd_walk() only needs to be
called on the kernel pagetable.  The user pgd page is then
pinned/unpinned along with the kernel pgd page.

xen_write_cr3 must write both the kernel and user cr3s.

The init_mm.pgd pagetable never has a user pagetable allocated for it,
because it can never be used while running usermode.

One awkward area is that early in boot the page structures are not
available.  No user pagetable can exist at that point, but it
complicates the logic to avoid looking at the page structure.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We need to do this, otherwise we can get a GPF on hypercall return
after TLS descriptor is cleared but %fs is still pointing to it.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Point the boot params cmd_line_ptr to the domain-builder-provided
command line.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Rewrite pgd_walk to deal with 64-bit address spaces.  There are two
notible features of 64-bit workspaces:

 1. The physical address is only 48 bits wide, with the upper 16 bits
    being sign extension; kernel addresses are negative, and userspace is
    positive.

 2. The Xen hypervisor mapping is at the negative-most address, just above
    the sign-extension hole.

1. means that we can't easily use addresses when traversing the space,
since we must deal with sign extension.  This rewrite expresses
everything in terms of pgd/pud/pmd indices, which means we don't need
to worry about the exact configuration of the virtual memory space.
This approach works equally well in 32-bit.

To deal with 2, assume the hole is between the uppermost userspace
address and PAGE_OFFSET.  For 64-bit this skips the Xen mapping hole.
For 32-bit, the hole is zero-sized.

In all cases, the uppermost kernel address is FIXADDR_TOP.

A side-effect of this patch is that the upper boundary is actually
handled properly, exposing a long-standing bug in 32-bit, which failed
to pin kernel pmd page.  The kernel pmd is not shared, and so must be
explicitly pinned, even though the kernel ptes are shared and don't
need pinning.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

xen-64: implement xen_load_gs_index()
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The x86_64 interrupt subsystem is oriented towards vectors, as opposed
to a flat irq space as it is in x86-32.  This patch adds a simple
identity irq->vector mapping so that we can continue to feed irqs into
do_IRQ() and get a good result.

Ideally x86_32 will unify with the 64-bit code and use vectors too.
At that point we can move to mapping event channels to vectors, which
will allow us to economise on irqs (so per-cpu event channels can
share irqs, rather than having to allocte one per cpu, for example).
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use callback_op hypercall to register callbacks in a 32/64-bit
independent way (64-bit doesn't need a code segment, but that detail
is hidden in XEN_CALLBACK).
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

swapgs is a no-op under Xen, because the hypervisor makes sure the
right version of %gs is current when switching between user and kernel
modes.  This means that the swapgs "implementation" can be inlined and
used when the stack is unsafe (usermode).  Unfortunately, it means
that disabling patching will result in a non-booting kernel...
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Xen pushes two extra words containing the values of rcx and r11.  This
pvop hook copies the words back into their appropriate registers, and
cleans them off the stack.  This leaves the stack in native form, so
the normal handler can run unchanged.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Changed to use the (to-be-)unified descriptor structs.
Signed-off-by: NEduardo Habkost <ehabkost@Rawhide-64.localdomain>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Make Xen's set_pte_mfn() use set_pte_vaddr rather than copying it.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We need to wait until the page structure is available to use the
proper pagetable page alloc/release operations, since they use struct
page to determine if a pagetable is pinned.

This happened to work in 32bit because nobody allocated new pagetable
pages in the interim between xen_pagetable_setup_done and
xen_post_allocator_init, but the 64-bit kenrel needs to allocate more
pagetable levels.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Someone's got to do it.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When building initial pagetables in 64-bit kernel the pud/pmd pointer may
be in ioremap/fixmap space, so we need to walk the pagetable to look up the
physical address.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arbitrary_virt_to_machine can truncate a machine address if its above
4G.  Cast the problem away.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Rearrange the pagetable initialization to share code with the 64-bit
kernel.  Rather than deferring anything to pagetable_setup_start, just
set up an initial pagetable in swapper_pg_dir early at startup, and
create an additional 8MB of physical memory mappings.  This matches
the native head_32.S mappings to a large degree, and allows the rest
of the pagetable setup to continue without much Xen vs. native
difference.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Early in boot, map a chunk of extra physical memory for use later on.
We need a pool of mapped pages to allocate further pages to construct
pagetables mapping all physical memory.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It also doesn't need the 32-bit hack version of set_pte for initial
pagetable construction, so just make it use the real thing.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Set up the initial pagetables to map the kernel mapping into the
physical mapping space.  This makes __va() usable, since it requires
physical mappings.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Split xen-asm into 32- and 64-bit files, and implement the 64-bit
variants.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add the Xen entrypoint and ELF notes to head_64.S.  Adapts xen-head.S
to compile either 32-bit or 64-bit.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

A number of random changes to make xen/smp.c compile in 64-bit mode.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>a
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

As a stopgap until Mike Travis's x86-64 gs-based percpu patches are
ready, provide workaround functions for x86_read/write_percpu for
Xen's use.

Specifically, this means that we can't really make use of vcpu
placement, because we can't use a single gs-based memory access to get
to vcpu fields.  So disable all that for now.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move all the smp_ops setup into smp.c, allowing a lot of things to
become static.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

x86_64 stores the active_mm in the pda, so fetch it from there.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We need extra pv_mmu_ops for 64-bit, to deal with the extra level of
pagetable.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Copy 64-bit definitions of various interface structures into place.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We need set_pte to work from a relatively early point, so enable it
from the start.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

add xen_timer_resume() hook.

Timer resume should be done after event channel is resumed.
add xen_arch_resume() hook when ipi becomes usable after resume.
After resume, some cpu specific resource must be reinitialized
on ia64 that can't be set by another cpu.

However available hooks is run once on only one cpu so that ipi has
to be used.

During stop_machine_run() ipi can't be used because interrupt is masked.
So add another hook after stop_machine_run().
Another approach might be use resume hook which is run by
device_resume(). However device_resume() may be executed on
suspend error recovery path.

So it is necessary to determine whether it is executed on real resume path
or error recovery path.
Signed-off-by: NIsaku Yamahata <yamahata@valinux.co.jp>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Print a backtrace if a multicall fails, to help with debugging.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Update arch/x86's use of page-aligned variables.  The change to
arch/x86/xen/mmu.c fixes an actual bug, but the rest are cleanups
and to set a precedent.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Call paravirt_pagetable_setup_{start,done}

These paravirt_ops functions were not being called on x86_64.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Rename the paravirtualized calculate_cpu_khz to calibrate_tsc.
In all cases, we actually calibrate_tsc and use that as the cpu_khz value.
Signed-off-by: NAlok N Kataria <akataria@vmware.com>
Signed-off-by: NDan Hecht <dhecht@vmware.com>
Cc: Dan Hecht <dhecht@vmware.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

64-bit Xen pushes a couple of extra words onto an exception frame.
Add a hook to deal with them.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Don't conflate sysret and sysexit; they're different instructions with
different semantics, and may be in use at the same time (at least
within the same kernel, depending on whether its an Intel or AMD
system).

sysexit - just return to userspace, does no register restoration of
    any kind; must explicitly atomically enable interrupts.

sysret - reloads flags from r11, so no need to explicitly enable
    interrupts on 64-bit, responsible for restoring usermode %gs
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citirx.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>