Currently KVM pretends that pages with EPT mappings never got
accessed.  This has some side effects in the VM, like swapping
out actively used guest pages and needlessly breaking up actively
used hugepages.

We can avoid those very costly side effects by emulating the
accessed bit for EPT PTEs, which should only be slightly costly
because pages pass through page_referenced infrequently.

TLB flushing is taken care of by kvm_mmu_notifier_clear_flush_young().

This seems to help prevent KVM guests from being swapped out when
they should not on my system.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

This patch introduces a generic function to find out the
host page size for a given gfn. This function is needed by
the kvm iommu code. This patch also simplifies the x86
host_mapping_level function.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

msr was tested above, so the second test is not needed.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression *x;
expression e;
identifier l;
@@

if (x == NULL || ...) {
    ... when forall
    return ...; }
... when != goto l;
    when != x = e
    when != &x
*x == NULL
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Avi Kivity <avi@redhat.com>

String constants that are continued on subsequent lines with \
are not good.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

Signed-off-by: Avi Kivity <avi@redhat.com>

This patch fixes kvm_fix_hypercall() to propagate X86EMUL_*
info generated by emulator_write_emulated() to its callers:
suggested by Marcelo.

The effect of this is x86_emulate_insn() will begin to handle
the page faults which occur in emulator_write_emulated():
this should be OK because emulator_write_emulated_onepage()
always injects page fault when emulator_write_emulated()
returns X86EMUL_PROPAGATE_FAULT.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

This patch fixes load_guest_segment_descriptor() to return
X86EMUL_PROPAGATE_FAULT when it tries to access the descriptor
table beyond the limit of it: suggested by Marcelo.

I have checked current callers of this helper function,
  - kvm_load_segment_descriptor()
  - kvm_task_switch()
and confirmed that this patch will change nothing in the
upper layers if we do not change the handling of this
return value from load_guest_segment_descriptor().

Next step: Although fixing the kvm_task_switch() to handle the
propagated faults properly seems difficult, and maybe not worth
it because TSS is not used commonly these days, we can fix
kvm_load_segment_descriptor(). By doing so, the injected #GP
becomes possible to be handled by the guest. The only problem
for this is how to differentiate this fault from the page faults
generated by kvm_read_guest_virt(). We may have to split this
function to achive this goal.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Enable optional parameter (default 0) - PCI segment (or domain) besides
BDF, when assigning PCI device to guest.
Signed-off-by: Zhai Edwin <edwin.zhai@intel.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

flexpriority_enabled implies cpu_has_vmx_virtualize_apic_accesses() returning
true, so we don't need this check here.
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Record failed msrs reads and writes, and the fact that they failed as well.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

- data is 64 bits wide, not unsigned long
- rw is confusingly named
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

On HW task switch newly loaded segments should me marked as accessed.
Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

When cr0.mp is clear, the guest doesn't expect a #NM in response to
a WAIT instruction.  Because we always keep cr0.mp set, it will get
a #NM, and potentially be confused.

Fix by keeping cr0.mp set only when the fpu is inactive, and passing
it through when inactive.
Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Analyzed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

commit 55fb1027c1cf9797dbdeab48180da530e81b1c39 doesn't update tlbcfg correctly.
Fix it.

And since guest OS likes 'fixed' hardware,
initialize tlbcfg everytime when guest access is useless.
So move this part to init code.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

commit 513579e3 change the way
we emulate PVR/PIR,
which left PVR/PIR uninitialized on E500, and make guest puzzled.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Latest kernel start to access l1csr0 to contron L1.
We just tell guest no operation is on going.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

If we fail to alloc page for vcpu->arch.mmu.pae_root, call to
free_mmu_pages() is unnecessary, which just do free the page
malloc for vcpu->arch.mmu.pae_root.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

'mask' is always a constant, so we can check whether it includes a bit that
might be owned by the guest very cheaply, and avoid the decache call.  Saves
a few hundred bytes of module text.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

None of the other registers have the shadow_ prefix.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

They have more general scope than the mmu.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Assume that if the guest executes clts, it knows what it's doing, and load the
guest fpu to prevent an #NM exception.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Not used anymore.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

This allows accessing the guest fpu from the instruction emulator, as well as
being symmetric with kvm_put_guest_fpu().
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Move to/from Control Registers chapter of Intel SDM says.  "Reserved bits
in CR0 remain clear after any load of those registers; attempts to set
them have no impact". Control Register chapter says "Bits 63:32 of CR0 are
reserved and must be written with zeros. Writing a nonzero value to any
of the upper 32 bits results in a general-protection exception, #GP(0)."

This patch tries to implement this twisted logic.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Reported-by: Lorenzo Martignoni <martignlo@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

The commit 0953ca73 "KVM: Simplify coalesced mmio initialization"
allocate kvm_coalesced_mmio_ring in the kvm_coalesced_mmio_init(), but
didn't discard the original allocation...
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

To enable proper debug register emulation under all conditions, trap
access to all DR0..7. This may be optimized later on.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Enhance mov dr instruction emulation used by SVM so that it properly
handles dr4/5: alias to dr6/7 if cr4.de is cleared. Otherwise return
EMULATE_FAIL which will let our only possible caller in that scenario,
ud_interception, re-inject UD.

We do not need to inject faults, SVM does this for us (exceptions take
precedence over instruction interceptions). For the same reason, the
value overflow checks can be removed.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

As we trap all debug register accesses, we do not need to switch real
DR6 at all. Clean up update_exception_bitmap at this chance, too.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Make sure DR4 and DR5 are aliased to DR6 and DR7, respectively, if
CR4.DE is not set.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Injecting GP without an error code is a bad idea (causes unhandled guest
exits). Moreover, we must not skip the instruction if we injected an
exception.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

The return values from x86_emulate_ops are defined
in kvm_emulate.h as macros X86EMUL_*.

But in emulate.c, we are comparing the return values
from these ops with 0 to check if they're X86EMUL_CONTINUE
or not: X86EMUL_CONTINUE is defined as 0 now.

To avoid possible mistakes in the future, this patch
substitutes "X86EMUL_CONTINUE" for "0" that are being
compared with the return values from x86_emulate_ops.

  We think that there are more places we should use these
  macros, but the meanings of rc values in x86_emulate_insn()
  were not so clear at a glance. If we use proper macros in
  this function, we would be able to follow the flow of each
  emulation more easily and, maybe, more securely.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

cleanup_srcu_struct on VM destruction remains broken:

BUG: unable to handle kernel paging request at ffffffffffffffff
IP: [<ffffffff802533d2>] srcu_read_lock+0x16/0x21
RIP: 0010:[<ffffffff802533d2>]  [<ffffffff802533d2>] srcu_read_lock+0x16/0x21
Call Trace:
 [<ffffffffa05354c4>] kvm_arch_vcpu_uninit+0x1b/0x48 [kvm]
 [<ffffffffa05339c6>] kvm_vcpu_uninit+0x9/0x15 [kvm]
 [<ffffffffa0569f7d>] vmx_free_vcpu+0x7f/0x8f [kvm_intel]
 [<ffffffffa05357b5>] kvm_arch_destroy_vm+0x78/0x111 [kvm]
 [<ffffffffa053315b>] kvm_put_kvm+0xd4/0xfe [kvm]

Move it to kvm_arch_destroy_vm.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>

Fix compilation warnings and wrong mask value.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

As Avi noted:

>There are two problems with the kernel failure report.  First, it
>doesn't report enough data - registers, surrounding instructions, etc.
>that are needed to explain what is going on.  Second, it can flood
>dmesg, which is a pretty bad thing to do.

So we remove the emulation failure report in handle_invalid_guest_state(),
and would inspected the guest using userspace tool in the future.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Needed by <asm/kvm_para.h>.
Signed-off-by: Avi Kivity <avi@redhat.com>

There are two spellings of "writable" in
arch/x86/kvm/mmu.c and paging_tmpl.h .

This patch renames is_writeble_pte() to is_writable_pte()
and makes grepping easy.

  New name is consistent with the definition of itself:
  return pte & PT_WRITABLE_MASK;
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>

Windows issues this hypercall after guest was spinning on a spinlock
for too many iterations.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

Implement HYPER-V apic MSRs. Spec defines three MSRs that speed-up
access to EOI/TPR/ICR apic registers for PV guests.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>