Per Ian Campbell suggestion to defend against future breakage
in case we expand the P2M values, incorporate the defines
in the string array.
Suggested-by: NIan Campbell <Ian.Campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We could be referencing the last + 1 element of level_name[]
array which would cause a pointer exception, because of the
initial setup of lvl=4.

[v1: No need to do this for type_name, pointed out by Ian Campbell]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We get:
linux/arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’:
linux/arch/x86/xen/enlighten.c:226: warning: ‘cx’ may be used uninitialized in this function
linux/arch/x86/xen/enlighten.c:240: note: ‘cx’ was declared here

and the cx is really not set but passed in the xen_cpuid instruction
which masks the value with returned masked_ecx from cpuid. This
can potentially lead to invalid data being stored in cx.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Replace calls to the Xen-specific xen_alloc_vm_area() and
xen_free_vm_area() functions with the generic equivalent
(alloc_vm_area() and free_vm_area()).

On x86, these were identical already.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In xen_memory_setup() all reserved regions and gaps are set to an
identity (1-1) p2m mapping.  If an available page has a PFN within one
of these 1-1 mappings it will become inaccessible (as it MFN is lost)
so release them before setting up the mapping.

This can make an additional 256 MiB or more of RAM available
(depending on the size of the reserved regions in the memory map) if
the initial pages overlap with reserved regions.

The 1:1 p2m mappings are also extended to cover partial pages.  This
fixes an issue with (for example) systems with a BIOS that puts the
DMI tables in a reserved region that begins on a non-page boundary.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Allow the extra memory (used by the balloon driver) to be in multiple
regions (typically two regions, one for low memory and one for high
memory).  This allows the balloon driver to increase the number of
available low pages (if the initial number if pages is small).

As a side effect, the algorithm for building the e820 memory map is
simpler and more obviously correct as the map supplied by the
hypervisor is (almost) used as is (in particular, all reserved regions
and gaps are preserved).  Only RAM regions are altered and RAM regions
above max_pfn + extra_pages are marked as unused (the region is split
in two if necessary).
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Allow the xen balloon driver to populate its list of extra pages from
more than one region of memory.  This will allow platforms to provide
(for example) a region of low memory and a region of high memory.

The maximum possible number of extra regions is 128 (== E820MAX) which
is quite large so xen_extra_mem is placed in __initdata.  This is safe
as both xen_memory_setup() and balloon_init() are in __init.

The balloon regions themselves are not altered (i.e., there is still
only the one region).
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

In xen_memory_setup() pages that occur in gaps in the memory map are
released back to Xen.  This reduces the domain's current page count in
the hypervisor.  The Xen balloon driver does not correctly decrease
its initial current_pages count to reflect this.  If 'delta' pages are
released and the target is adjusted the resulting reservation is
always 'delta' less than the requested target.

This affects dom0 if the initial allocation of pages overlaps the PCI
memory region but won't affect most domU guests that have been setup
with pseudo-physical memory maps that don't have gaps.

Fix this by accouting for the released pages when starting the balloon
driver.

If the domain's targets are managed by xapi, the domain may eventually
run out of memory and die because xapi currently gets its target
calculations wrong and whenever it is restarted it always reduces the
target by 'delta'.
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Xen PV on HVM guests require PCI support because they need the
xen-platform-pci driver in order to initialize xenbus.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If we want to use granted pages for AIO, changing the mappings of a user
vma and the corresponding p2m is not enough, we also need to update the
kernel mappings accordingly.
Currently this is only needed for pages that are created for user usages
through /dev/xen/gntdev. As in, pages that have been in use by the
kernel and use the P2M will not need this special mapping.
However there are no guarantees that in the future the kernel won't
start accessing pages through the 1:1 even for internal usage.

In order to avoid the complexity of dealing with highmem, we allocated
the pages lowmem.
We issue a HYPERVISOR_grant_table_op right away in
m2p_add_override and we remove the mappings using another
HYPERVISOR_grant_table_op in m2p_remove_override.
Considering that m2p_add_override and m2p_remove_override are called
once per page we use multicalls and hypercall batching.

Use the kmap_op pointer directly as argument to do the mapping as it is
guaranteed to be present up until the unmapping is done.
Before issuing any unmapping multicalls, we need to make sure that the
mapping has already being done, because we need the kmap->handle to be
set correctly.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
[v1: Removed GRANT_FRAME_BIT usage]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We use the page->private field and hence should use the proper
macros and set proper bits. Also WARN_ON in case somebody
tries to overwrite our data.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We dropped a lot of the MMU debugfs in favour of using
tracing API - but there is one which just provides
mostly static information that was made invisible by this change.

Bring it back.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The numbers obtained from the hypervisor really can't ever lead to an
overflow here, only the original calculation going through the order
of the range could have. This avoids the (as Jeremy points outs)
somewhat ugly NULL-based calculation here.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The patch "xen: use maximum reservation to limit amount of usable RAM"
(d312ae87) breaks machines that
do not use 'dom0_mem=' argument with:

reserve RAM buffer: 000000133f2e2000 - 000000133fffffff
(XEN) mm.c:4976:d0 Global bit is set to kernel page fffff8117e
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 0 (vcpu#0) crashed on cpu#0:
...

The reason being that the last E820 entry is created using the
'extra_pages' (which is based on how many pages have been freed).
The mentioned git commit sets the initial value of 'extra_pages'
using a hypercall which returns the number of pages (if dom0_mem
has been used) or -1 otherwise. If the later we return with
MAX_DOMAIN_PAGES as basis for calculation:

    return min(max_pages, MAX_DOMAIN_PAGES);

and use it:

     extra_limit = xen_get_max_pages();
     if (extra_limit >= max_pfn)
             extra_pages = extra_limit - max_pfn;
     else
             extra_pages = 0;

which means we end up with extra_pages = 128GB in PFNs (33554432)
- 8GB in PFNs (2097152, on this specific box, can be larger or smaller),
and then we add that value to the E820 making it:

  Xen: 00000000ff000000 - 0000000100000000 (reserved)
  Xen: 0000000100000000 - 000000133f2e2000 (usable)

which is clearly wrong. It should look as so:

  Xen: 00000000ff000000 - 0000000100000000 (reserved)
  Xen: 0000000100000000 - 000000027fbda000 (usable)

Naturally this problem does not present itself if dom0_mem=max:X
is used.

CC: stable@kernel.org
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

PV spinlocks cannot possibly work with the current code because they are
enabled after pvops patching has already been done, and because PV
spinlocks use a different data structure than native spinlocks so we
cannot switch between them dynamically. A spinlock that has been taken
once by the native code (__ticket_spin_lock) cannot be taken by
__xen_spin_lock even after it has been released.
Reported-and-Tested-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We have hit a couple of customer bugs where they would like to
use those parameters to run an UP kernel - but both of those
options turn of important sources of interrupt information so
we end up not being able to boot. The correct way is to
pass in 'dom0_max_vcpus=1' on the Xen hypervisor line and
the kernel will patch itself to be a UP kernel.

Fixes bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=637308

CC: stable@kernel.org
Acked-by: NIan Campbell <Ian.Campbell@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

If vmalloc page_fault happens inside of interrupt handler with interrupts
disabled then on exit path from exception handler when there is no pending
interrupts, the following code (arch/x86/xen/xen-asm_32.S:112):

	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
	sete XEN_vcpu_info_mask(%eax)

will enable interrupts even if they has been previously disabled according to
eflags from the bounce frame (arch/x86/xen/xen-asm_32.S:99)

	testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp)
	setz XEN_vcpu_info_mask(%eax)

Solution is in setting XEN_vcpu_info_mask only when it should be set
according to
	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
but not clearing it if there isn't any pending events.

Reproducer for bug is attached to RHBZ 707552

CC: stable@kernel.org
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Use the domain's maximum reservation to limit the amount of extra RAM
for the memory balloon. This reduces the size of the pages tables and
the amount of reserved low memory (which defaults to about 1/32 of the
total RAM).

On a system with 8 GiB of RAM with the domain limited to 1 GiB the
kernel reports:

Before:

Memory: 627792k/4472000k available

After:

Memory: 549740k/11132224k available

A increase of about 76 MiB (~1.5% of the unused 7 GiB).  The reserved
low memory is also reduced from 253 MiB to 32 MiB.  The total
additional usable RAM is 329 MiB.

For dom0, this requires at patch to Xen ('x86: use 'dom0_mem' to limit
the number of pages for dom0') (c/s 23790)

CC: stable@kernel.org
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The tracing code used sched_clock() to get tracing timestamps, which
ends up calling xen_clocksource_read().  xen_clocksource_read() must
disable preemption, but if preemption tracing is enabled, this results
in infinite recursion.

I've only noticed this when boot-time tracing tests are enabled, but it
seems like a generic bug.  It looks like it would also affect
kvm_clocksource_read().
Reported-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>

Steven Rostedt says we should use CONFIG_EVENT_TRACING.

Cc:Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Fix regression for HVM case on older (<4.1.1) hypervisors caused by

  commit 99bbb3a8
  Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
  Date:   Thu Dec 2 17:55:10 2010 +0000

    xen: PV on HVM: support PV spinlocks and IPIs

This change replaced the SMP operations with event based handlers without
taking into account that this only works when the hypervisor supports
callback vectors. This causes unexplainable hangs early on boot for
HVM guests with more than one CPU.

BugLink: http://bugs.launchpad.net/bugs/791850

CC: stable@kernel.org
Signed-off-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-and-Reported-by: NStefan Bader <stefan.bader@canonical.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The order-based approach is not only less efficient (requiring a shift
and a compare, typical generated code looking like this

	mov	eax, [machine_to_phys_order]
	mov	ecx, eax
	shr	ebx, cl
	test	ebx, ebx
	jnz	...

whereas a direct check requires just a compare, like in

	cmp	ebx, [machine_to_phys_nr]
	jae	...

), but also slightly dangerous in the 32-on-64 case - the element
address calculation can wrap if the next power of two boundary is
sufficiently far away from the actual upper limit of the table, and
hence can result in user space addresses being accessed (with it being
unknown what may actually be mapped there).

Additionally, the elimination of the mistaken use of fls() here (should
have been __fls()) fixes a latent issue on x86-64 that would trigger
if the code was run on a system with memory extending beyond the 44-bit
boundary.

CC: stable@kernel.org
Signed-off-by: NJan Beulich <jbeulich@novell.com>
[v1: Based on Jeremy's feedback]
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

We don' use it anymore and there are more false positives.

This reverts commit fc25151d.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

with CONFIG_XEN and CONFIG_FTRACE set we get this:

arch/x86/xen/trace.c:22: error: ‘__HYPERVISOR_console_io’ undeclared here (not in a function)
arch/x86/xen/trace.c:22: error: array index in initializer not of integer type
arch/x86/xen/trace.c:22: error: (near initialization for ‘xen_hypercall_names’)
arch/x86/xen/trace.c:23: error: ‘__HYPERVISOR_physdev_op_compat’ undeclared here (not in a function)

Issue was that the definitions of __HYPERVISOR were not pulled
if CONFIG_XEN_PRIVILEGED_GUEST was not set.
Reported-by: NRandy Dunlap <rdunlap@xenotime.net>
Acked-by: NRandy Dunlap <rdunlap@xenotime.net>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Three places in the kernel assume that the only long mode CPL 3
selector is __USER_CS.  This is not true on Xen -- Xen's sysretq
changes cs to the magic value 0xe033.

Two of the places are corner cases, but as of "x86-64: Improve
vsyscall emulation CS and RIP handling"
(c9712944), vsyscalls will segfault
if called with Xen's extra CS selector.  This causes a panic when
older init builds die.

It seems impossible to make Xen use __USER_CS reliably without
taking a performance hit on every system call, so this fixes the
tests instead with a new paravirt op.  It's a little ugly because
ptrace.h can't include paravirt.h.
Signed-off-by: NAndy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/f4fcb3947340d9e96ce1054a432f183f9da9db83.1312378163.git.luto@mit.eduReported-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Xen needs to handle VVAR_PAGE, introduced in git commit:
9fd67b4e
x86-64: Give vvars their own page

Otherwise we die during bootup with a message like:

(XEN) mm.c:940:d10 Error getting mfn 1888 (pfn 1e3e48) from L1 entry
      8000000001888465 for l1e_owner=10, pg_owner=10
(XEN) mm.c:5049:d10 ptwr_emulate: could not get_page_from_l1e()
[    0.000000] BUG: unable to handle kernel NULL pointer dereference at (null)
[    0.000000] IP: [<ffffffff8103a930>] xen_set_pte+0x20/0xe0
Signed-off-by: NAndy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/4659478ed2f3480938f96491c2ecbe2b2e113a23.1312378163.git.luto@mit.eduReviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

WARN message should not complain
 "Failed to release memory %lx-%lx err=%d\n"
                           ^^^^^^^
about range when it fails to release just one page,
instead it should say what pfn is not freed.

In addition line:
 printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: "
 ...
 printk(KERN_CONT "%lu pages freed\n", len);
will be broken if WARN in between this line is fired. So fix it
by using a single printk for this.
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Use correct format specifier for unsigned long.
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Apparently we wanted CONFIG_FTRACE rather the CONFIG_FUNCTION_TRACER.
Reported-by: NSander Eikelenboom <linux@eikelenboom.it>
Tested-by: NSander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

When a Xen Dom0 kernel boots on a hypervisor, it gets access
to the raw-hardware ACPI tables.  While it parses the idle tables
for the hypervisor's beneift, it uses HLT for its own idle.

Rather than have xen scribble on pm_idle and access default_idle,
have it simply disable_cpuidle() so acpi_idle will not load and
architecture default HLT will be used.

cc: xen-devel@lists.xensource.com
Tested-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

When CONFIG_FUNCTION_TRACER is disabled, compilation fails as follows:
  CC      arch/x86/xen/setup.o
In file included from arch/x86/include/asm/xen/hypercall.h:42,
                 from arch/x86/xen/setup.c:19:
include/trace/events/xen.h:31: warning: 'struct multicall_entry' declared inside parameter list
include/trace/events/xen.h:31: warning: its scope is only this definition or declaration, which is probably not what you want
include/trace/events/xen.h:31: warning: 'struct multicall_entry' declared inside parameter list
include/trace/events/xen.h:31: warning: 'struct multicall_entry' declared inside parameter list
include/trace/events/xen.h:31: warning: 'struct multicall_entry' declared inside parameter list
[...]
arch/x86/xen/trace.c:5: error: '__HYPERVISOR_set_trap_table' undeclared here (not in a function)
arch/x86/xen/trace.c:5: error: array index in initializer not of integer type
arch/x86/xen/trace.c:5: error: (near initialization for 'xen_hypercall_names')
arch/x86/xen/trace.c:6: error: '__HYPERVISOR_mmu_update' undeclared here (not in a function)
arch/x86/xen/trace.c:6: error: array index in initializer not of integer type
arch/x86/xen/trace.c:6: error: (near initialization for 'xen_hypercall_names')

Fix this by making sure struct multicall_entry has a declaration in
scope at all times, and don't bother compiling xen/trace.c when tracing
is disabled.
Reported-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

The CPU would prefer small offsets.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Singleton calls seem to end up being pretty common, so just
directly call the hypercall rather than going via multicall.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

It's useful - and probably should be a config - but its very heavyweight,
especially with the tracing stuff to help sort out problems.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Make sure the fastpath code is inlined.  Batch the page permission change
and the pin/unpin, and make sure that it can be batched with any
adjacent set_pte/pmd/etc operations.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>