[GIT PULL] KVM: x86: Xen clock/timekeeping changes for 7.3

[Sean Christopherson <seanjc@google.com>]

Three small Xen-specific changes.  I was hoping to include a much larger pile
of kvmclock and timekeeping changes from David, hence the "clocks" name.
Another 21 patches _this_ close to making the 7.3 cut, and there's another 25
coming on top of those.

While kvmclock is on your mind (or at least, close to being on your mind), can
you weigh on on the KVM_SET_CLOCK_GUEST discussion[*]?  I hopefully, finally
understand the code well enough to be comfortable merging the code, but your
input on the uAPI would be super helpful.  Thanks!

[*] https://lore.kernel.org/all/ants4VjfAiblaWsl@google.com

The following changes since commit 8cdeaa50eae8dad34885515f62559ee83e7e8dda:

  Linux 7.2-rc2 (2026-07-05 14:44:06 -1000)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-clocks-7.3

for you to fetch changes up to 7d3bd21e457bd091beb982553fcf32fd9ee5929f:

  KVM: x86: Remove runtime Xen TSC frequency CPUID update (2026-08-07 09:11:56 -0700)

----------------------------------------------------------------
KVM x86 PV clocks and timekeeping related changes for 7.3

 - Remove a defunct masterclock update from kvm_xen_shared_info_init() that
   could result in corrupting kvmclock, for a lose definition or "corrupting",
   due to triggering an unnecessary switch to/from masterclock mode.

 - Skip Xen runstate time updates if time has effectively gone backwards, so
   that the guest doesn't report 100% steal time for a very, very long time.

 - Drop KVM's runtime updates of the Xen PV timing CPUID leaf, as KVM was
   updating the wrong sub-leaf, and upstream KVM will soon provide all the
   information needed by userspace to populate the CPUID field itself.

----------------------------------------------------------------
David Woodhouse (3):
      KVM: x86/xen: Do not corrupt KVM clock in kvm_xen_shared_info_init()
      KVM: x86/xen: Prevent runstate times from becoming negative
      KVM: x86: Remove runtime Xen TSC frequency CPUID update

 arch/x86/kvm/cpuid.c | 16 ----------------
 arch/x86/kvm/xen.c   | 30 ++++++++++++++++++++++--------
 arch/x86/kvm/xen.h   | 13 -------------
 3 files changed, 22 insertions(+), 37 deletions(-)