vmx_complete_interrupts() assumes that the exception is always injected,
so it can be dropped by kvm_clear_exception_queue().  However,
an exception cannot be injected immediately if it is: 1) originally
destined to a nested guest; 2) trapped to cause a vmexit; 3) happening
right after VMLAUNCH/VMRESUME, i.e. when nested_run_pending is true.

This patch applies to exceptions the same algorithm that is used for
NMIs, replacing exception.reinject with "exception.injected" (equivalent
to nmi_injected).

exception.pending now represents an exception that is queued and whose
side effects (e.g., update RFLAGS.RF or DR7) have not been applied yet.
If exception.pending is true, the exception might result in a nested
vmexit instead, too (in which case the side effects must not be applied).

exception.injected instead represents an exception that is going to be
injected into the guest at the next vmentry.
Reported-by: NRadim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Use kvm_event_needs_reinjection() encapsulation.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch exposes 5 level page table feature to the VM.
At the same time, the canonical virtual address checking is
extended to support both 48-bits and 57-bits address width.
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Extends the shadow paging code, so that 5 level shadow page
table can be constructed if VM is running in 5 level paging
mode.

Also extends the ept code, so that 5 level ept table can be
constructed if maxphysaddr of VM exceeds 48 bits. Unlike the
shadow logic, KVM should still use 4 level ept table for a VM
whose physical address width is less than 48 bits, even when
the VM is running in 5 level paging mode.
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
[Unconditionally reset the MMU context in kvm_cpuid_update.
 Changing MAXPHYADDR invalidates the reserved bit bitmasks.
 - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A guest may not be configured to support XSAVES/XRSTORS, even when the host
does. If the guest does not support XSAVES/XRSTORS, clear the secondary
execution control so that the processor will raise #UD.

Also clear the "allowed-1" bit for XSAVES/XRSTORS exiting in the
IA32_VMX_PROCBASED_CTLS2 MSR, and pass through VMCS12's control in
the VMCS02.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A guest may not be configured to support RDSEED, even when the host
does. If the guest does not support RDSEED, intercept the instruction
and synthesize #UD. Also clear the "allowed-1" bit for RDSEED exiting
in the IA32_VMX_PROCBASED_CTLS2 MSR.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A guest may not be configured to support RDRAND, even when the host
does. If the guest does not support RDRAND, intercept the instruction
and synthesize #UD. Also clear the "allowed-1" bit for RDRAND exiting
in the IA32_VMX_PROCBASED_CTLS2 MSR.
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Currently, secondary execution controls are divided in three groups:

- static, depending mostly on the module arguments or the processor
  (vmx_secondary_exec_control)

- static, depending on CPUID (vmx_cpuid_update)

- dynamic, depending on nested VMX or local APIC state

Because walking CPUID is expensive, prepare_vmcs02 is using only
the first group.  This however is unnecessarily complicated.  Just
cache the static secondary execution controls, and then prepare_vmcs02
does not need to compute them every time.  Computation of all static
secondary execution controls is now kept in a single function,
vmx_compute_secondary_exec_control.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We already always set that type but don't check if it is supported. Also
for nVMX, we only support WB for now. Let's just require it.
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Don't use shifts, tag them correctly as EPTP and use better matching
names (PWL vs. GAW).
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

There is currently some confusion between nested and L1 GPAs.  The
assignment to "direct" in kvm_mmu_page_fault tries to fix that, but
it is not enough.  What this patch does is fence off the MMIO cache
completely when using shadow nested page tables, since we have neither
a GVA nor an L1 GPA to put in the cache.  This also allows some
simplifications in kvm_mmu_page_fault and FNAME(page_fault).

The EPT misconfig likewise does not have an L1 GPA to pass to
kvm_io_bus_write, so that must be skipped for guest mode.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
[Changed comment to say "GPAs" instead of "L1's physical addresses", as
 per David's review. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

When a guest causes a page fault which requires emulation, the
vcpu->arch.gpa_available flag is set to indicate that cr2 contains a
valid GPA.

Currently, emulator_read_write_onepage() makes use of gpa_available flag
to avoid a guest page walk for a known MMIO regions. Lets not limit
the gpa_available optimization to just MMIO region. The patch extends
the check to avoid page walk whenever gpa_available flag is set.
Signed-off-by: NBrijesh Singh <brijesh.singh@amd.com>
[Fix EPT=0 according to Wanpeng Li's fix, plus ensure VMX also uses the
 new code. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
[Moved "ret < 0" to the else brach, as per David's review. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Calling handle_mmio_page_fault() has been unnecessary since commit
e9ee956e ("KVM: x86: MMU: Move handle_mmio_page_fault() call to
kvm_mmu_page_fault()", 2016-02-22).

handle_mmio_page_fault() can now be made static.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Let's reuse the function introduced with eptp switching.

We don't explicitly have to check against enable_ept_ad_bits, as this
is implicitly done when checking against nested_vmx_ept_caps in
valid_ept_address().
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This is the same as commit 14727754 ("kvm: svm: Add support for
additional SVM NPF error codes", 2016-11-23), but for Intel processors.
In this case, the exit qualification field's bit 8 says whether the
EPT violation occurred while translating the guest's final physical
address or rather while translating the guest page tables.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Reported by syzkaller:

The kvm-intel.unrestricted_guest=0

   WARNING: CPU: 5 PID: 1014 at /home/kernel/data/kvm/arch/x86/kvm//x86.c:7227 kvm_arch_vcpu_ioctl_run+0x38b/0x1be0 [kvm]
   CPU: 5 PID: 1014 Comm: warn_test Tainted: G        W  OE   4.13.0-rc3+ #8
   RIP: 0010:kvm_arch_vcpu_ioctl_run+0x38b/0x1be0 [kvm]
   Call Trace:
    ? put_pid+0x3a/0x50
    ? rcu_read_lock_sched_held+0x79/0x80
    ? kmem_cache_free+0x2f2/0x350
    kvm_vcpu_ioctl+0x340/0x700 [kvm]
    ? kvm_vcpu_ioctl+0x340/0x700 [kvm]
    ? __fget+0xfc/0x210
    do_vfs_ioctl+0xa4/0x6a0
    ? __fget+0x11d/0x210
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x23/0xc2
    ? __this_cpu_preempt_check+0x13/0x20

The syszkaller folks reported a residual mmio emulation request to userspace
due to vm86 fails to emulate inject real mode interrupt(fails to read CS) and
incurs a triple fault. The vCPU returns to userspace with vcpu->mmio_needed == true
and KVM_EXIT_SHUTDOWN exit reason. However, the syszkaller testcase constructs
several threads to launch the same vCPU, the thread which lauch this vCPU after
the thread whichs get the vcpu->mmio_needed == true and KVM_EXIT_SHUTDOWN will
trigger the warning.

   #define _GNU_SOURCE
   #include <pthread.h>
   #include <stdio.h>
   #include <stdlib.h>
   #include <string.h>
   #include <sys/wait.h>
   #include <sys/types.h>
   #include <sys/stat.h>
   #include <sys/mman.h>
   #include <fcntl.h>
   #include <unistd.h>
   #include <linux/kvm.h>
   #include <stdio.h>

   int kvmcpu;
   struct kvm_run *run;

   void* thr(void* arg)
   {
     int res;
     res = ioctl(kvmcpu, KVM_RUN, 0);
     printf("ret1=%d exit_reason=%d suberror=%d\n",
         res, run->exit_reason, run->internal.suberror);
     return 0;
   }

   void test()
   {
     int i, kvm, kvmvm;
     pthread_t th[4];

     kvm = open("/dev/kvm", O_RDWR);
     kvmvm = ioctl(kvm, KVM_CREATE_VM, 0);
     kvmcpu = ioctl(kvmvm, KVM_CREATE_VCPU, 0);
     run = (struct kvm_run*)mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, kvmcpu, 0);
     srand(getpid());
     for (i = 0; i < 4; i++) {
       pthread_create(&th[i], 0, thr, 0);
       usleep(rand() % 10000);
     }
     for (i = 0; i < 4; i++)
       pthread_join(th[i], 0);
   }

   int main()
   {
     for (;;) {
       int pid = fork();
       if (pid < 0)
         exit(1);
       if (pid == 0) {
         test();
         exit(0);
       }
       int status;
       while (waitpid(pid, &status, __WALL) != pid) {}
     }
     return 0;
   }

This patch fixes it by resetting the vcpu->mmio_needed once we receive
the triple fault to avoid the residue.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Tested-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

get_cpl requires vcpu_load, so we must cache the result (whether the
vcpu was preempted when its cpl=0) in kvm_vcpu_arch.
Signed-off-by: NLongpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If a vcpu exits due to request a user mode spinlock, then
the spinlock-holder may be preempted in user mode or kernel mode.
(Note that not all architectures trap spin loops in user mode,
only AMD x86 and ARM/ARM64 currently do).

But if a vcpu exits in kernel mode, then the holder must be
preempted in kernel mode, so we should choose a vcpu in kernel mode
as a more likely candidate for the lock holder.

This introduces kvm_arch_vcpu_in_kernel() to decide whether the
vcpu is in kernel-mode when it's preempted.  kvm_vcpu_on_spin's
new argument says the same of the spinning VCPU.
Signed-off-by: NLongpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add guest_cpuid_clear() and use it instead of kvm_find_cpuid_entry().
Also replace some uses of kvm_find_cpuid_entry() with guest_cpuid_has().
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch turns guest_cpuid_has_XYZ(cpuid) into guest_cpuid_has(cpuid,
X86_FEATURE_XYZ), which gets rid of many very similar helpers.

When seeing a X86_FEATURE_*, we can know which cpuid it belongs to, but
this information isn't in common code, so we recreate it for KVM.

Add some BUILD_BUG_ONs to make sure that it runs nicely.
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When L2 uses vmfunc, L0 utilizes the associated vmexit to
emulate a switching of the ept pointer by reloading the
guest MMU.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBandan Das <bsd@redhat.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Expose VMFUNC in MSRs and VMCS fields. No actual VMFUNCs are enabled.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBandan Das <bsd@redhat.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Enable VMFUNC in the secondary execution controls.  This simplifies the
changes necessary to expose it to nested hypervisors.  VMFUNCs still
cause #UD when invoked.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBandan Das <bsd@redhat.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Let's also just use the underlying functions directly here.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
[Rebased on top of 9f744c59 ("KVM: nVMX: do not pin the VMCS12")]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

nested_get_page() just sounds confusing. All we want is a page from G1.
This is even unrelated to nested.

Let's introduce kvm_vcpu_gpa_to_page() so we don't get too lengthy
lines.
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
[Squash pasto fix from Wanpeng Li. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Expose the "Enable INVPCID" secondary execution control to the guest
and properly reflect the exit reason.

In addition, before this patch the guest was always running with
INVPCID enabled, causing pcid.flat's "Test on INVPCID when disabled"
test to fail.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

------------[ cut here ]------------
 WARNING: CPU: 5 PID: 2288 at arch/x86/kvm/vmx.c:11124 nested_vmx_vmexit+0xd64/0xd70 [kvm_intel]
 CPU: 5 PID: 2288 Comm: qemu-system-x86 Not tainted 4.13.0-rc2+ #7
 RIP: 0010:nested_vmx_vmexit+0xd64/0xd70 [kvm_intel]
Call Trace:
  vmx_check_nested_events+0x131/0x1f0 [kvm_intel]
  ? vmx_check_nested_events+0x131/0x1f0 [kvm_intel]
  kvm_arch_vcpu_ioctl_run+0x5dd/0x1be0 [kvm]
  ? vmx_vcpu_load+0x1be/0x220 [kvm_intel]
  ? kvm_arch_vcpu_load+0x62/0x230 [kvm]
  kvm_vcpu_ioctl+0x340/0x700 [kvm]
  ? kvm_vcpu_ioctl+0x340/0x700 [kvm]
  ? __fget+0xfc/0x210
  do_vfs_ioctl+0xa4/0x6a0
  ? __fget+0x11d/0x210
  SyS_ioctl+0x79/0x90
  do_syscall_64+0x8f/0x750
  ? trace_hardirqs_on_thunk+0x1a/0x1c
  entry_SYSCALL64_slow_path+0x25/0x25

This can be reproduced by booting L1 guest w/ 'noapic' grub parameter, which
means that tells the kernel to not make use of any IOAPICs that may be present
in the system.

Actually external_intr variable in nested_vmx_vmexit() is the req_int_win
variable passed from vcpu_enter_guest() which means that the L0's userspace
requests an irq window. I observed the scenario (!kvm_cpu_has_interrupt(vcpu) &&
L0's userspace reqeusts an irq window) is true, so there is no interrupt which
L1 requires to inject to L2, we should not attempt to emualte "Acknowledge
interrupt on exit" for the irq window requirement in this scenario.

This patch fixes it by not attempt to emulate "Acknowledge interrupt on exit"
if there is no L1 requirement to inject an interrupt to L2.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
[Added code comment to make it obvious that the behavior is not correct.
 We should do a userspace exit with open interrupt window instead of the
 nested VM exit.  This patch still improves the behavior, so it was
 accepted as a (temporary) workaround.]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

The host physical addresses of L1's Virtual APIC Page and Posted
Interrupt descriptor are loaded into the VMCS02. The CPU may write
to these pages via their host physical address while L2 is running,
bypassing address-translation-based dirty tracking (e.g. EPT write
protection). Mark them dirty on every exit from L2 to prevent them
from getting out of sync with dirty tracking.

Also mark the virtual APIC page and the posted interrupt descriptor
dirty when KVM is virtualizing posted interrupt processing.
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

According to the Intel SDM, software cannot rely on the current VMCS to be
coherent after a VMXOFF or shutdown. So this is a valid way to handle VMCS12
flushes.

24.11.1 Software Use of Virtual-Machine Control Structures
...
  If a logical processor leaves VMX operation, any VMCSs active on
  that logical processor may be corrupted (see below). To prevent
  such corruption of a VMCS that may be used either after a return
  to VMX operation or on another logical processor, software should
  execute VMCLEAR for that VMCS before executing the VMXOFF instruction
  or removing power from the processor (e.g., as part of a transition
  to the S3 and S4 power states).
...

This fixes a "suspicious rcu_dereference_check() usage!" warning during
kvm_vm_release() because nested_release_vmcs12() calls
kvm_vcpu_write_guest_page() without holding kvm->srcu.
Signed-off-by: NDavid Matlack <dmatlack@google.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Since the current implementation of VMCS12 does a memcpy in and out
of guest memory, we do not need current_vmcs12 and current_vmcs12_page
anymore.  current_vmptr is enough to read and write the VMCS12.

And David Matlack noted:

  This patch also fixes dirty tracking (memslot->dirty_bitmap) of the
  VMCS12 page by using kvm_write_guest. nested_release_page() only marks
  the struct page dirty.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
[Added David Matlack's note and nested_release_page_clean() fix.]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

There are three issues in nested_vmx_check_exception:

1) it is not taking PFEC_MATCH/PFEC_MASK into account, as reported
by Wanpeng Li;

2) it should rebuild the interruption info and exit qualification fields
from scratch, as reported by Jim Mattson, because the values from the
L2->L0 vmexit may be invalid (e.g. if an emulated instruction causes
a page fault, the EPT misconfig's exit qualification is incorrect).

3) CR2 and DR6 should not be written for exception intercept vmexits
(CR2 only for AMD).

This patch fixes the first two and adds a comment about the last,
outlining the fix.

Cc: Jim Mattson <jmattson@google.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Do this in the caller of nested_vmx_vmexit instead.

nested_vmx_check_exception was doing a vmwrite to the vmcs02's
VM_EXIT_INTR_ERROR_CODE field, so that prepare_vmcs12 would move
the field to vmcs12->vm_exit_intr_error_code.  However that isn't
possible on pre-Haswell machines.  Moving the vmcs12 write to the
callers fixes it.
Reported-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
[Changed nested_vmx_reflect_vmexit() return type to (int)1 from (bool)1,
 thanks to fengguang.wu@intel.com]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Run kvm-unit-tests/eventinj.flat in L1 w/ ept=0 on both L0 and L1:

Before NMI IRET test
Sending NMI to self
NMI isr running stack 0x461000
Sending nested NMI to self
After nested NMI to self
Nested NMI isr running rip=40038e
After iret
After NMI to self
FAIL: NMI

Commit 4c4a6f79 (KVM: nVMX: track NMI blocking state separately
for each VMCS) tracks NMI blocking state separately for vmcs01 and
vmcs02. However it is not enough:

 - The L2 (kvm-unit-tests/eventinj.flat) generates NMI that will fault
   on IRET, so the L2 can generate #PF which can be intercepted by L0.
 - L0 walks L1's guest page table and sees the mapping is invalid, it
   resumes the L1 guest and injects the #PF into L1.  At this point the
   vmcs02 has nmi_known_unmasked=true.
 - L1 sets set bit 3 (blocking by NMI) in the interruptibility-state field
   of vmcs12 (and fixes the shadow page table) before resuming L2 guest.
 - L1 executes VMRESUME to resume L2, causing a vmexit to L0
 - during VMRESUME emulation, prepare_vmcs02 sets bit 3 in the
   interruptibility-state field of vmcs02, but nmi_known_unmasked is
   still true.
 - L2 immediately exits to L0 with another page fault, because L0 still has
   not updated the NGVA->HPA page tables.  However, nmi_known_unmasked is
   true so vmx_recover_nmi_blocking does not do anything.

The fix is to update nmi_known_unmasked when preparing vmcs02 from vmcs12.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The PI vector for L0 and L1 must be different. If dest vcpu0
is in guest mode while vcpu1 is delivering a non-nested PI to
vcpu0, there wont't be any vmexit so that the non-nested interrupt
will be delayed.
Signed-off-by: NWincy Van <fanwenyi0529@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This can be reproduced by EPT=1, unrestricted_guest=N, emulate_invalid_state=Y
or EPT=0, the trace of kvm-unit-tests/taskswitch2.flat is like below, it tries
to emulate invalid guest state task-switch:

kvm_exit: reason TASK_SWITCH rip 0x0 info 40000058 0
kvm_emulate_insn: 42000:0:0f 0b (0x2)
kvm_emulate_insn: 42000:0:0f 0b (0x2) failed
kvm_inj_exception: #UD (0x0)
kvm_entry: vcpu 0
kvm_exit: reason TASK_SWITCH rip 0x0 info 40000058 0
kvm_emulate_insn: 42000:0:0f 0b (0x2)
kvm_emulate_insn: 42000:0:0f 0b (0x2) failed
kvm_inj_exception: #UD (0x0)
......................

It appears that the task-switch emulation updates rflags (and vm86
flag) only after the segments are loaded, causing vmx->emulation_required
to be set, when in fact invalid guest state emulation is not needed.

This patch fixes it by updating vmx->emulation_required after the
rflags (and vm86 flag) is updated in task-switch emulation.

Thanks Radim for moving the update to vmx__set_flags and adding Paolo's
suggestion for the check.
Suggested-by: NNadav Amit <nadav.amit@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Immediately following MOV-to-SS/POP-to-SS, VM-entry is
disallowed. This check comes after the check for a valid VMCS. When
this check fails, the instruction pointer should fall through to the
next instruction, the ALU flags should be set to indicate VMfailValid,
and the VM-instruction error should be set to 26 ("VM entry with
events blocked by MOV SS").
Signed-off-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

vmx_recover_nmi_blocking is using a cached value of the guest
interruptibility info, which is stored in vmx->nmi_known_unmasked.
vmx_recover_nmi_blocking is run for both normal and nested guests,
so the cached value must be per-VMCS.

This fixes eventinj.flat in a nested non-EPT environment.  With EPT it
works, because the EPT violation handler doesn't have the
vmx->nmi_known_unmasked optimization (it is unnecessary because, unlike
vmx_recover_nmi_blocking, it can just look at the exit qualification).

Thanks to Wanpeng Li for debugging the testcase and providing an initial
patch.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Adds another flag bit (bit 2) to MSR_KVM_ASYNC_PF_EN. If bit 2 is 1,
async page faults are delivered to L1 as #PF vmexits; if bit 2 is 0,
kvm_can_do_async_pf returns 0 if in guest mode.

This is similar to what svm.c wanted to do all along, but it is only
enabled for Linux as L1 hypervisor.  Foreign hypervisors must never
receive async page faults as vmexits, because they'd probably be very
confused about that.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Add an nested_apf field to vcpu->arch.exception to identify an async page
fault, and constructs the expected vm-exit information fields. Force a
nested VM exit from nested_vmx_check_exception() if the injected #PF is
async page fault.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>