Originally from Jeremy Fitzhardinge.

So code can be reused.
Acked-by: NGlauber Costa <glommer@parallels.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Commit de2d1a52 ("KVM: Fix register corruption in pvclock_scale_delta")
introduced a mul instruction that may have only a memory operand; the
assembler therefore cannot select the correct size:

   pvclock.s:229: Error: no instruction mnemonic suffix given and no register
operands; can't size instruction

In this example the assembler is:

         #APP
         mul -48(%rbp) ; shrd $32, %rdx, %rax
         #NO_APP

A simple solution is to use mulq.
Signed-off-by: NDuncan Sands <baldrick@free.fr>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The 128-bit multiply in pvclock.h was missing an output constraint for
EDX which caused a register corruption to appear.  Thanks to Ulrich for
diagnosing the EDX corruption and Avi for providing this fix.
Signed-off-by: NZachary Amsden <zamsden@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

If the guest domain has been suspend/resumed or migrated, then the
system clock backing the pvclock clocksource may revert to a smaller
value (ie, can be non-monotonic across the migration/save-restore).

Make sure we zero last_value in that case so that the domain
continues to see clock updates.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The scale_delta function for shift / multiply with 31-bit
precision moves to a common header so it can be used by both
kernel and kvm module.
Signed-off-by: NZachary Amsden <zamsden@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

This patch removes one padding byte and transform it into a flags
field. New versions of guests using pvclock will query these flags
upon each read.

Flags, however, will only be interpreted when the guest decides to.
It uses the pvclock_valid_flags function to signal that a specific
set of flags should be taken into consideration. Which flags are valid
are usually devised via HV negotiation.
Signed-off-by: NGlauber Costa <glommer@redhat.com>
CC: Jeremy Fitzhardinge <jeremy@goop.org>
Acked-by: NZachary Amsden <zamsden@redhat.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

KVM intends to use paravirt code to calibrate khz. Xen
current code will do just fine. So as a first step, factor out
code to pvclock.c.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.

The format:

1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
   distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
   underscores.
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>

This patch adds structs for the paravirt clocksource ABI
used by both xen and kvm (pvclock-abi.h).

It also adds some helper functions to read system time and
wall clock time from a paravirtual clocksource (pvclock.[ch]).
They are based on the xen code.  They are enabled using
CONFIG_PARAVIRT_CLOCK.

Subsequent patches of this series will put the code in use.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>