If #PF happens during delivery of an exception into L2 and L1 also do
not have the page mapped in its shadow page table then L0 needs to
generate vmexit to L2 with original event in IDT_VECTORING_INFO, but
current code combines both exception and generates #DF instead. Fix that
by providing nVMX specific function to handle page faults during page
table walk that handles this case correctly.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

All exceptions should be checked for intercept during delivery to L2,
but we check only #PF currently. Drop nested_run_pending while we are
at it since exception cannot be injected during vmentry anyway.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
[Renamed the nested_vmx_check_exception function. - Paolo]
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If an exception causes vmexit directly it should not be reported in
IDT_VECTORING_INFO during the exit. For that we need to be able to
distinguish between exception that is injected into nested VM and one that
is reinjected because its delivery failed. Fortunately we already have
mechanism to do so for nested SVM, so here we just use correct function
to requeue exceptions and make sure that reinjected exception is not
moved to IDT_VECTORING_INFO during vmexit emulation and not re-checked
for interception during delivery.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

EXIT_REASON_VMLAUNCH/EXIT_REASON_VMRESUME exit does not mean that nested
VM will actually run during next entry. Move setting nested_run_pending
closer to vmentry emulation code and move its clearing close to vmexit to
minimize amount of code that will erroneously run with nested_run_pending
set.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Now that we provide EPT support, there is no reason to torture our
guests by hiding the relieving unrestricted guest mode feature. We just
need to relax CR0 checks for always-on bits as PE and PG can now be
switched off.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Implement and advertise VM_EXIT_SAVE_IA32_EFER. L0 traps EFER writes
unconditionally, so we always find the current L2 value in the
architectural state.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Fiddling with CR3 for L2 is L1's job. It may set its own, different
identity map or simple leave it alone if unrestricted guest mode is
enabled. This also fixes reading back the current CR3 on L2 exits for
reporting it to L1.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

kvm_set_cr0 performs checks on the state transition that may prevent
loading L1's cr0. For now we rely on the hardware to catch invalid
states loaded by L1 into its VMCS. Still, consistency checks on the host
state part of the VMCS on guest entry will have to be improved later on.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Set "blocked by NMI" flag if EPT violation happens during IRET from NMI
otherwise NMI can be called recursively causing stack corruption.
Signed-off-by: NGleb Natapov <gleb@redhat.com>

After nested vmentry stale cache can be used to reload L2 PDPTR pointers
which will cause L2 guest to fail. Fix it by invalidating cache on nested
vmentry emulation.

https://bugzilla.kernel.org/show_bug.cgi?id=60830Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

These will happen due to MMIO.
Suggested-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Advertise VM_EXIT_SAVE_IA32_PAT and VM_EXIT_LOAD_IA32_PAT.
Signed-off-by: NArthur Chunqi Li <yzt356@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Do not report that we can enter the guest in 64-bit mode if the host is
32-bit only. This is not supported by KVM.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

At least WB must be possible.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When asking vmx to load the PAT MSR for us while switching from L1 to L2
or vice versa, we have to update arch.pat as well as it may later be
used again to load or read out the MSR content.
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Tested-by: NArthur Chunqi Li <yzt356@gmail.com>
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Some trivial code cleanups not really related to nested EPT.
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Some additional comments to preexisting code:
Explain who (L0 or L1) handles EPT violation and misconfiguration exits.
Don't mention "shadow on either EPT or shadow" as the only two options.
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This is the last patch of the basic Nested EPT feature, so as to allow
bisection through this patch series: The guest will not see EPT support until
this last patch, and will not attempt to use the half-applied feature.
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If we let L1 use EPT, we should probably also support the INVEPT instruction.

In our current nested EPT implementation, when L1 changes its EPT table
for L2 (i.e., EPT12), L0 modifies the shadow EPT table (EPT02), and in
the course of this modification already calls INVEPT. But if last level
of shadow page is unsync not all L1's changes to EPT12 are intercepted,
which means roots need to be synced when L1 calls INVEPT. Global INVEPT
should not be different since roots are synced by kvm_mmu_load() each
time EPTP02 changes.
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

KVM's existing shadow MMU code already supports nested TDP. To use it, we
need to set up a new "MMU context" for nested EPT, and create a few callbacks
for it (nested_ept_*()). This context should also use the EPT versions of
the page table access functions (defined in the previous patch).
Then, we need to switch back and forth between this nested context and the
regular MMU context when switching between L1 and L2 (when L1 runs this L2
with EPT).
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Inject nEPT fault to L1 guest. This patch is original from Xinhao.
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The existing code for handling cr3 and related VMCS fields during nested
exit and entry wasn't correct in all cases:

If L2 is allowed to control cr3 (and this is indeed the case in nested EPT),
during nested exit we must copy the modified cr3 from vmcs02 to vmcs12, and
we forgot to do so. This patch adds this copy.

If L0 isn't controlling cr3 when running L2 (i.e., L0 is using EPT), and
whoever does control cr3 (L1 or L2) is using PAE, the processor might have
saved PDPTEs and we should also save them in vmcs12 (and restore later).
Reviewed-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Recent KVM, since http://kerneltrap.org/mailarchive/linux-kvm/2010/5/2/6261577
switch the EFER MSR when EPT is used and the host and guest have different
NX bits. So if we add support for nested EPT (L1 guest using EPT to run L2)
and want to be able to run recent KVM as L1, we need to allow L1 to use this
EFER switching feature.

To do this EFER switching, KVM uses VM_ENTRY/EXIT_LOAD_IA32_EFER if available,
and if it isn't, it uses the generic VM_ENTRY/EXIT_MSR_LOAD. This patch adds
support for the former (the latter is still unsupported).

Nested entry and exit emulation (prepare_vmcs_02 and load_vmcs12_host_state,
respectively) already handled VM_ENTRY/EXIT_LOAD_IA32_EFER correctly. So all
that's left to do in this patch is to properly advertise this feature to L1.

Note that vmcs12's VM_ENTRY/EXIT_LOAD_IA32_EFER are emulated by L0, by using
vmx_set_efer (which itself sets one of several vmcs02 fields), so we always
support this feature, regardless of whether the host supports it.
Reviewed-by: NOrit Wasserman <owasserm@redhat.com>
Signed-off-by: NNadav Har'El <nyh@il.ibm.com>
Signed-off-by: NJun Nakajima <jun.nakajima@intel.com>
Signed-off-by: NXinhao Xu <xinhao.xu@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

After commit 21feb4eb tr base is zeroed
during vmexit. Set it to L1's HOST_TR_BASE. This should fix
https://bugzilla.kernel.org/show_bug.cgi?id=60679Reported-by: NYongjie Ren <yongjie.ren@intel.com>
Reviewed-by: NArthur Chunqi Li <yzt356@gmail.com>
Tested-by: NYongjie Ren <yongjie.ren@intel.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

During nested vmentry into vm86 mode a vcpu state is found to be incorrect
because rflags does not have VM flag set since it is read from the cache
and has L1's value instead of L2's. If emulate_invalid_guest_state=1 L0
KVM tries to emulate it, but emulation does not work for nVMX and it
never should happen anyway. Fix that by using vmx_set_rflags() to set
rflags during nested vmentry which takes care of updating register cache.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The next patch will reuse it for other userspace exits than MMIO,
namely debug events.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When L2 exits to L1, segment infomations of L1 are not set correctly.
According to Intel SDM 27.5.2(Loading Host Segment and Descriptor
Table Registers), segment base/limit/access right of L1 should be
set to some designed value when L2 exits to L1. This patch fixes
this.
Signed-off-by: NArthur Chunqi Li <yzt356@gmail.com>
Reviewed-by: NGleb Natapov <gnatapov@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Fix read/write to IA32_FEATURE_CONTROL MSR in nested environment.

This patch simulate this MSR in nested_vmx and the default value is
0x0. BIOS should set it to 0x5 before VMXON. After setting the lock
bit, write to it will cause #GP(0).

Another QEMU patch is also needed to handle emulation of reset
and migration. Reset to vCPU should clear this MSR and migration
should reserve value of it.

This patch is based on Nadav's previous commit.
http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/88478Signed-off-by: NNadav Har'El <nyh@math.technion.ac.il>
Signed-off-by: NArthur Chunqi Li <yzt356@gmail.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Use a const pointer type instead of casting away the const qualifier
from const arrays. Keep the pointer array on the stack, nonetheless.
Making it static just increases the object size.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

Set rflags after successfully emulateing VMXON/VMXOFF in VMX.
Signed-off-by: NArthur Chunqi Li <yzt356@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Move nested_vmx_succeed/nested_vmx_failInvalid/nested_vmx_failValid
ahead of handle_vmon to eliminate double declaration in the same
file
Signed-off-by: NArthur Chunqi Li <yzt356@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Some userspaces do not preserve unusable property. Since usable
segment has to be present according to VMX spec we can use present
property to amend userspace bug by making unusable segment always
nonpresent. vmx_segment_access_rights() already marks nonpresent segment
as unusable.

Cc: stable@vger.kernel.org # 3.9+
Reported-by: NStefan Pietsch <stefan.pietsch@lsexperts.de>
Tested-by: NStefan Pietsch <stefan.pietsch@lsexperts.de>
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add a tracepoint write_tsc_offset for tracing TSC offset change.
We want to merge ftrace's trace data of guest OSs and the host OS using
TSC for timestamp in chronological order. We need "TSC offset" values for
each guest when merge those because the TSC value on a guest is always the
host TSC plus guest's TSC offset. If we get the TSC offset values, we can
calculate the host TSC value for each guest events from the TSC offset and
the event TSC value. The host TSC values of the guest events are used when we
want to merge trace data of guests and the host in chronological order.
(Note: the trace_clock of both the host and the guest must be set x86-tsc in
this case)

This tracepoint also records vcpu_id which can be used to merge trace data for
SMP guests. A merge tool will read TSC offset for each vcpu, then the tool
converts guest TSC values to host TSC values for each vcpu.

TSC offset is stored in the VMCS by vmx_write_tsc_offset() or
vmx_adjust_tsc_offset(). KVM executes the former function when a guest boots.
The latter function is executed when kvm clock is updated. Only host can read
TSC offset value from VMCS, so a host needs to output TSC offset value
when TSC offset is changed.

Since the TSC offset is not often changed, it could be overwritten by other
frequent events while tracing. To avoid that, I recommend to use a special
instance for getting this event:

1. set a instance before booting a guest
 # cd /sys/kernel/debug/tracing/instances
 # mkdir tsc_offset
 # cd tsc_offset
 # echo x86-tsc > trace_clock
 # echo 1 > events/kvm/kvm_write_tsc_offset/enable

2. boot a guest
Signed-off-by: NYoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

This patch tries to introduce a very simple and scale way to invalidate
all mmio sptes - it need not walk any shadow pages and hold mmu-lock

KVM maintains a global mmio valid generation-number which is stored in
kvm->memslots.generation and every mmio spte stores the current global
generation-number into his available bits when it is created

When KVM need zap all mmio sptes, it just simply increase the global
generation-number. When guests do mmio access, KVM intercepts a MMIO #PF
then it walks the shadow page table and get the mmio spte. If the
generation-number on the spte does not equal the global generation-number,
it will go to the normal #PF handler to update the mmio spte

Since 19 bits are used to store generation-number on mmio spte, we zap all
mmio sptes when the number is round
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Define some meaningful names instead of raw code
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Bit 1 in the x86 EFLAGS is always set.  Name the macro something that
actually tries to explain what it is all about, rather than being a
tautology.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/n/tip-f10rx5vjjm6tfnt8o1wseb3v@git.kernel.org

Let mmio spte only use bit62 and bit63 on upper 32 bits, then bit 52 ~ bit 61
can be used for other purposes
Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Reviewed-by: NGleb Natapov <gleb@redhat.com>
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The invalid guest state emulation loop does not check halt_request
which causes 100% cpu loop while guest is in halt and in invalid
state, but more serious issue is that this leaves halt_request set, so
random instruction emulated by vm86 #GP exit can be interpreted
as halt which causes guest hang. Fix both problems by handling
halt_request in emulation loop.
Reported-by: NTomas Papan <tomas.papan@gmail.com>
Tested-by: NTomas Papan <tomas.papan@gmail.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: NGleb Natapov <gleb@redhat.com>

With VMX, enable_irq_window can now return -EBUSY, in which case an
immediate exit shall be requested before entering the guest. Account for
this also in enable_nmi_window which uses enable_irq_window in absence
of vnmi support, e.g.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

While a nested run is pending, vmx_queue_exception is only called to
requeue exceptions that were previously picked up via
vmx_cancel_injection. Therefore, we must not check for PF interception
by L1, possibly causing a bogus nested vmexit.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>