VMX hardware can cache the contents of a vcpu's vmcs.  This cache needs
to be flushed when migrating a vcpu to another cpu, or (which is the case
that interests us here) when disabling hardware virtualization on a cpu.

The current implementation of decaching iterates over the list of all vcpus,
picks the ones that are potentially cached on the cpu that is being offlined,
and flushes the cache.  The problem is that it uses mutex_trylock() to gain
exclusive access to the vcpu, which fires off a (benign) warning about using
the mutex in an interrupt context.

To avoid this, and to make things generally nicer, add a new per-cpu list
of potentially cached vcus.  This makes the decaching code much simpler.  The
list is vmx-specific since other hardware doesn't have this issue.

[andrea: fix crash on suspend/resume]
Signed-off-by: NAndrea Arcangeli <andrea@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

KVM turns off hardware virtualization extensions during reboot, in order
to disassociate the memory used by the virtualization extensions from the
processor, and in order to have the system in a consistent state.
Unfortunately virtual machines may still be running while this goes on,
and once virtualization extensions are turned off, any virtulization
instruction will #UD on execution.

Fix by adding an exception handler to virtualization instructions; if we get
an exception during reboot, we simply spin waiting for the reset to complete.
If it's a true exception, BUG() so we can have our stack trace.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

This patch moves the trace entry for APIC accesses from the VMX code to the
generic lapic code. This way APIC accesses from SVM will also be traced.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Noticed by sparse:
arch/x86/kvm/vmx.c:1583:6: warning: symbol 'vmx_disable_intercept_for_msr' was not declared. Should it be static?
arch/x86/kvm/x86.c:3406:5: warning: symbol 'kvm_task_switch_16' was not declared. Should it be static?
arch/x86/kvm/x86.c:3429:5: warning: symbol 'kvm_task_switch_32' was not declared. Should it be static?
arch/x86/kvm/mmu.c:1968:6: warning: symbol 'kvm_mmu_remove_one_alloc_mmu_page' was not declared. Should it be static?
arch/x86/kvm/mmu.c:2014:6: warning: symbol 'mmu_destroy_caches' was not declared. Should it be static?
arch/x86/kvm/lapic.c:862:5: warning: symbol 'kvm_lapic_get_base' was not declared. Should it be static?
arch/x86/kvm/i8254.c:94:5: warning: symbol 'pit_get_gate' was not declared. Should it be static?
arch/x86/kvm/i8254.c:196:5: warning: symbol '__pit_timer_fn' was not declared. Should it be static?
arch/x86/kvm/i8254.c:561:6: warning: symbol '__inject_pit_timer_intr' was not declared. Should it be static?
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

It's never used and the comments refer to nonatomic and retry
interchangably. So get rid of it.
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Switching msrs can occur either synchronously as a result of calls to
the msr management functions (usually in response to the guest touching
virtualized msrs), or asynchronously when preempting a kvm thread that has
guest state loaded.  If we're unlucky enough to have the two at the same
time, host msrs are corrupted and the machine goes kaput on the next syscall.

Most easily triggered by Windows Server 2008, as it does a lot of msr
switching during bootup.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Clear CR4.VMXE in hardware_disable. There's no reason to leave it set
after doing a VMXOFF.

VMware Workstation 6.5 checks CR4.VMXE as a proxy for whether the CPU is
in VMX mode, so leaving VMXE set means we'll refuse to power on. With this
change the user can power on after unloading the kvm-intel module. I
tested on kvm-67 and kvm-69.
Signed-off-by: NEli Collins <ecollins@vmware.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Migrate the PIT timer to the physical CPU which vcpu0 is scheduled on,
similarly to what is done for the LAPIC timers, otherwise PIT interrupts
will be delayed until an unrelated event causes an exit.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

[aliguory: plug leak]
Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The function get_tdp_level() provided the number of tdp level for EPT and
NPT rather than the NPT specific macro.
Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Trace markers allow userspace to trace execution of a virtual machine
in order to monitor its performance.
Signed-off-by: NFeng (Eric) Liu <eric.e.liu@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Unify slots_lock acquision around vcpu_run(). This is simpler and less
error-prone.

Also fix some callsites that were not grabbing the lock properly.

[avi: drop slots_lock while in guest mode to avoid holding the lock
      for indefinite periods]
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

MSR Bitmap controls whether the accessing of an MSR causes VM Exit.
Eliminating exits on automatically saved and restored MSRs yields a
small performance gain.
Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This emulates the x86 hardware task switch mechanism in software, as it is
unsupported by either vmx or svm.  It allows operating systems which use it,
like freedos, to run as kvm guests.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Useful for debugging.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Most Intel hosts have a stable tsc, and playing with the offset only
reduces accuracy.  By limiting tsc offset adjustment only to forward updates,
we effectively disable tsc offset adjustment on these hosts.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Names like 'set_cr3()' look dangerously close to affecting the host.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The x86 desc_struct unification allows us to remove segment_descriptor.h.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Looking at Intel Volume 3b, page 148, table 20-11 and noticed
that the field name is 'Deliver' not 'Deliever'.  Attached patch changes
the define name and its user in vmx.c
Signed-off-by: NRyan Harper <ryanh@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

To allow access to the EFER register in 32bit KVM the EFER specific code has to
be exported to the x86 generic code. This patch does this in a backwards
compatible manner.

[avi: add check for EFER-less hosts]
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This patch aligns the bits the guest can set in the EFER register with the
features in the host processor. Currently it lets EFER.NX disabled if the
processor does not support it and enables EFER.LME and EFER.LMA only for KVM on
64 bit hosts.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

To allow TLB entries to be retained across VM entry and VM exit, the VMM
can now identify distinct address spaces through a new virtual-processor ID
(VPID) field of the VMCS.

[avi: drop vpid_sync_all()]
[avi: add "cc" to asm constraints]
Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

init_rmode_tss was forgotten during the conversion from mmap_sem to
slots_lock.

INFO: task qemu-system-x86:3748 blocked for more than 120 seconds.
Call Trace:
 [<ffffffff8053d100>] __down_read+0x86/0x9e
 [<ffffffff8053fb43>] do_page_fault+0x346/0x78e
 [<ffffffff8053d235>] trace_hardirqs_on_thunk+0x35/0x3a
 [<ffffffff8053dcad>] error_exit+0x0/0xa9
 [<ffffffff8035a7a7>] copy_user_generic_string+0x17/0x40
 [<ffffffff88099a8a>] :kvm:kvm_write_guest_page+0x3e/0x5f
 [<ffffffff880b661a>] :kvm_intel:init_rmode_tss+0xa7/0xf9
 [<ffffffff880b7d7e>] :kvm_intel:vmx_vcpu_reset+0x10/0x38a
 [<ffffffff8809b9a5>] :kvm:kvm_arch_vcpu_setup+0x20/0x53
 [<ffffffff8809a1e4>] :kvm:kvm_vm_ioctl+0xad/0x1cf
 [<ffffffff80249dea>] __lock_acquire+0x4f7/0xc28
 [<ffffffff8028fad9>] vfs_ioctl+0x21/0x6b
 [<ffffffff8028fd75>] do_vfs_ioctl+0x252/0x26b
 [<ffffffff8028fdca>] sys_ioctl+0x3c/0x5e
 [<ffffffff8020b01b>] system_call_after_swapgs+0x7b/0x80
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The vmx hardware state restore restores the tss selector and base address, but
not its length.  Usually, this does not matter since most of the tss contents
is within the default length of 0x67.  However, if a process is using ioperm()
to grant itself I/O port permissions, an additional bitmap within the tss,
but outside the default length is consulted.  The effect is that the process
will receive a SIGSEGV instead of transparently accessing the port.

Fix by restoring the tss length.  Note that i386 had this working already.

Closes bugzilla 10246.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

KVM tries to run as much as possible with the guest msrs loaded instead of
host msrs, since switching msrs is very expensive.  It also tries to minimize
the number of msrs switched according to the guest mode; for example,
MSR_LSTAR is needed only by long mode guests.  This optimization is done by
setup_msrs().

However, we must not change which msrs are switched while we are running with
guest msr state:

 - switch to guest msr state
 - call setup_msrs(), removing some msrs from the list
 - switch to host msr state, leaving a few guest msrs loaded

An easy way to trigger this is to kexec an x86_64 linux guest.  Early during
setup, the guest will switch EFER to not include SCE.  KVM will stop saving
MSR_LSTAR, and on the next msr switch it will leave the guest LSTAR loaded.
The next host syscall will end up in a random location in the kernel.

Fix by reloading the host msrs before changing the msr list.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

alloc_apic_access_page() can sleep, while vmx_vcpu_setup is called
inside a non preemptable region. Move it after put_cpu().
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This patch replaces the mmap_sem lock for the memory slots with a new
kvm private lock, it is needed beacuse untill now there were cases where
kvm accesses user memory while holding the mmap semaphore.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

When executing a test program called "crashme", we found the KVM guest cannot
survive more than ten seconds, then encounterd kernel panic. The basic concept
of "crashme" is generating random assembly code and trying to execute it.

After some fixes on emulator insn validity judgment, we found it's hard to
get the current emulator handle the invalid instructions correctly, for the
#UD trap for hypercall patching caused troubles. The problem is, if the opcode
itself was OK, but combination of opcode and modrm_reg was invalid, and one
operand of the opcode was memory (SrcMem or DstMem), the emulator will fetch
the memory operand first rather than checking the validity, and may encounter
an error there. For example, ".byte 0xfe, 0x34, 0xcd" has this problem.

In the patch, we simply check that if the invalid opcode wasn't vmcall/vmmcall,
then return from emulate_instruction() and inject a #UD to guest. With the
patch, the guest had been running for more than 12 hours.
Signed-off-by: NFeng (Eric) Liu <eric.e.liu@intel.com>
Signed-off-by: NSheng Yang <sheng.yang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Convert the synchronization of the shadow handling to a separate mmu_lock
spinlock.

Also guard fetch() by mmap_sem in read-mode to protect against alias
and memslot changes.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Do not hold kvm->lock mutex across the entire pagefault code,
only acquire it in places where it is necessary, such as mmu
hash list, active list, rmap and parent pte handling.

Allow concurrent guest walkers by switching walk_addr() to use
mmap_sem in read-mode.

And get rid of the lockless __gfn_to_page.

[avi: move kvm_mmu_pte_write() locking inside the function]
[avi: add locking for real mode]
[avi: fix cmpxchg locking]
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

FlexPriority accelerates the tpr without any patching.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This paves the way for multiple architecture support.  Note that while
ioapic.c could potentially be shared with ia64, it is also moved.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Add printk_ratelimit check in front of printk.  This prevents spamming
of the message during 32-bit ubuntu 6.06server install.  Previously, it
would hang during the partition formatting stage.
Signed-off-by: NRyan Harper <ryanh@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This patches moves two fields round_robin_prev_vcpu and tss to kvm_arch.
Signed-off-by: NZhang Xiantao <xiantao.zhang@intel.com>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>