When we tested KVM under memory pressure, with THP enabled on the host,
we noticed that MMU notifier took a long time to invalidate huge pages.

Since the invalidation was done with mmu_lock held, it not only wasted
the CPU but also made the host harder to respond.

This patch mitigates this by using kvm_handle_hva_range().
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

When guest's memory is backed by THP pages, MMU notifier needs to call
kvm_unmap_hva(), which in turn leads to kvm_handle_hva(), in a loop to
invalidate a range of pages which constitute one huge page:

  for each page
    for each memslot
      if page is in memslot
        unmap using rmap

This means although every page in that range is expected to be found in
the same memslot, we are forced to check unrelated memslots many times.
If the guest has more memslots, the situation will become worse.

Furthermore, if the range does not include any pages in the guest's
memory, the loop over the pages will just consume extra time.

This patch, together with the following patches, solves this problem by
introducing kvm_handle_hva_range() which makes the loop look like this:

  for each memslot
    for each page in memslot
      unmap using rmap

In this new processing, the actual work is converted to a loop over rmap
which is much more cache friendly than before.
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

This restricts hva handling in mmu code and makes it easier to extend
kvm_handle_hva() so that it can treat a range of addresses later in this
patch series.
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

We can treat every level uniformly.
Signed-off-by: NTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

This reverts commit f9808b7f.
After commit 'kvm: switch to apic_set_eoi_write, apic_write'
the stubs are no longer needed as kvm does not look at apicdrivers anymore.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Use apic_set_eoi_write, apic_write to avoid meedling in core apic
driver data structures directly.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

KVM PV EOI optimization overrides eoi_write apic op with its own
version. Add an API for this to avoid meddling with core x86 apic driver
data structures directly.

For KVM use, we don't need any guarantees about when the switch to the
new op will take place, so it could in theory use this API after SMP init,
but it currently doesn't, and restricting callers to early init makes it
clear that it's safe as it won't race with actual APIC driver use.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NAvi Kivity <avi@redhat.com>

ppc queue from Alex Graf:

 * Prepare some of the booke code for 64 bit support
 * BookE: Fix ESR flag in DSI
 * BookE: Add rfci emulation

* 'for-upstream' of git://github.com/agraf/linux-2.6:
  KVM: PPC: Critical interrupt emulation support
  KVM: PPC: e500mc: Fix tlbilx emulation for 64-bit guests
  KVM: PPC64: booke: Set interrupt computation mode for 64-bit host
  KVM: PPC: bookehv: Add ESR flag to Data Storage Interrupt
  KVM: PPC: bookehv64: Add support for std/ld emulation.
  booke: Added crit/mc exception handler for e500v2
  booke/bookehv: Add host crit-watchdog exception support
Signed-off-by: NAvi Kivity <avi@redhat.com>

This patch handles PCID/INVPCID for guests.

Process-context identifiers (PCIDs) are a facility by which a logical processor
may cache information for multiple linear-address spaces so that the processor
may retain cached information when software switches to a different linear
address space. Refer to section 4.10.1 in IA32 Intel Software Developer's Manual
Volume 3A for details.

For guests with EPT, the PCID feature is enabled and INVPCID behaves as running
natively.
For guests without EPT, the PCID feature is disabled and INVPCID triggers #UD.
Signed-off-by: NJunjie Mao <junjie.mao@intel.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

While debugging I noticed that unlike all the other hypervisor code in the
kernel, kvm does not have an entry for x86_hyper which is used in
detect_hypervisor_platform() which results in a nice printk in the
syslog.  This is only really a stub function but it
does make kvm more consistent with the other hypervisors.
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marcelo Tostatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: NAvi Kivity <avi@redhat.com>

rfci instruction and CSRR0/1 registers are emulated.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NStuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

tlbilxva emulation was using an u32 variable for guest effective address.
Replace it with gva_t type to handle 64-bit guests.
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

64-bit host needs to remain in 64-bit mode when an exception take place.
Set interrupt computaion mode in EPCR register.
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

ESR register is required by Data Storage Interrupt handling code.
Add the specific flag to the interrupt handler.
Signed-off-by: NMihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Add support for std/ld emulation.
Signed-off-by: NVarun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Watchdog is taken at critical exception level. So this patch
is tested with host watchdog exception happening when guest
is running.
Signed-off-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Signed-off-by: NBharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Document fast page fault and mmu-lock in locking.txt
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The P bit of page fault error code is missed in this tracepoint, fix it by
passing the full error code
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

To see what happen on this path and help us to optimize it
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

If the the present bit of page fault error code is set, it indicates
the shadow page is populated on all levels, it means what we do is
only modify the access bit which can be done out of mmu-lock

Currently, in order to simplify the code, we only fix the page fault
caused by write-protect on the fast path
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

This bit indicates whether the spte can be writable on MMU, that means
the corresponding gpte is writable and the corresponding gfn is not
protected by shadow page protection

In the later path, SPTE_MMU_WRITEABLE will indicates whether the spte
can be locklessly updated
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

mmu_spte_update() is the common function, we can easily audit the path
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Export the present bit of page fault error code, the later patch
will use it
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Use __drop_large_spte to cleanup this function and comment spte_write_protect
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Introduce a common function to abstract spte write-protect to
cleanup the code
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

The reture value of __rmap_write_protect is either 1 or 0, use
true/false instead of these
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

Our emulation should be complete enough that we can emulate guests
while they are in big real mode, or in a mode transition that is not
virtualizable without unrestricted guest support.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Opcode 0F 00 /3.  Encountered during Windows XP secondary processor bringup.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Guest software doesn't actually depend on it, but vmx will refuse us
entry if we don't.  Set the bit in both the cached segment and memory,
just to be nice.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Some operations want to modify the descriptor later on, so save the
address for future use.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Opcode 0F 00 /2. Used by isolinux durign the protected mode transition.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Opcodes 0F C8 - 0F CF.

Used by the SeaBIOS cdrom code (though not in big real mode).
Signed-off-by: NAvi Kivity <avi@redhat.com>

If instruction emulation fails, report it properly to userspace.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Process the event, possibly injecting an interrupt, before continuing.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Opcode C8.

Only ENTER with lexical nesting depth 0 is implemented, since others are
very rare.  We'll fail emulation if nonzero lexical depth is used so data
is not corrupted.
Signed-off-by: NAvi Kivity <avi@redhat.com>

This allows us to reuse the code without populating ctxt->src and
overriding ctxt->op_bytes.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Commit 2adb5ad9 removed ByteOp from MOVZX/MOVSX, replacing them by
SrcMem8, but neglected to fix the dependency in the emulation code
on ByteOp.  This caused the instruction not to have any effect in
some circumstances.

Fix by replacing the check for ByteOp with the equivalent src.op_bytes == 1.
Signed-off-by: NAvi Kivity <avi@redhat.com>

Opcode 9F.
Signed-off-by: NAvi Kivity <avi@redhat.com>

If we return early from an invalid guest state emulation loop, make
sure we return to it later if the guest state is still invalid.
Signed-off-by: NAvi Kivity <avi@redhat.com>