Commit Graph

197 Commits

Author SHA1 Message Date
Avi Kivity d5696725b2 KVM: VMX: Fix comparison of guest efer with stale host value
update_transition_efer() masks out some efer bits when deciding whether
to switch the msr during guest entry; for example, NX is emulated using the
mmu so we don't need to disable it, and LMA/LME are handled by the hardware.

However, with shared msrs, the comparison is made against a stale value;
at the time of the guest switch we may be running with another guest's efer.

Fix by deferring the mask/compare to the actual point of guest entry.

Noted by Marcelo.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:34:20 +02:00
Sheng Yang 046d87103a KVM: VMX: Disable unrestricted guest when EPT disabled
Otherwise would cause VMEntry failure when using ept=0 on unrestricted guest
supported processors.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:25 +02:00
Jan Kiszka 3cfc3092f4 KVM: x86: Add KVM_GET/SET_VCPU_EVENTS
This new IOCTL exports all yet user-invisible states related to
exceptions, interrupts, and NMIs. Together with appropriate user space
changes, this fixes sporadic problems of vmsave/restore, live migration
and system reset.

[avi: future-proof abi by adding a flags field]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:25 +02:00
Avi Kivity 65ac726404 KVM: VMX: Report unexpected simultaneous exceptions as internal errors
These happen when we trap an exception when another exception is being
delivered; we only expect these with MCEs and page faults.  If something
unexpected happens, things probably went south and we're better off reporting
an internal error and freezing.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:24 +02:00
Avi Kivity a9c7399d6c KVM: Allow internal errors reported to userspace to carry extra data
Usually userspace will freeze the guest so we can inspect it, but some
internal state is not available.  Add extra data to internal error
reporting so we can expose it to the debugger.  Extra data is specific
to the suberror.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:24 +02:00
Avi Kivity 92c0d90015 KVM: VMX: Remove vmx->msr_offset_efer
This variable is used to communicate between a caller and a callee; switch
to a function argument instead.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:23 +02:00
Marcelo Tosatti 7c93be44a4 KVM: VMX: move CR3/PDPTR update to vmx_set_cr3
GUEST_CR3 is updated via kvm_set_cr3 whenever CR3 is modified from
outside guest context. Similarly pdptrs are updated via load_pdptrs.

Let kvm_set_cr3 perform the update, removing it from the vcpu_run
fast path.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Acked-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:22 +02:00
Avi Kivity 26bb0981b3 KVM: VMX: Use shared msr infrastructure
Instead of reloading syscall MSRs on every preemption, use the new shared
msr infrastructure to reload them at the last possible minute (just before
exit to userspace).

Improves vcpu/idle/vcpu switches by about 2000 cycles (when EFER needs to be
reloaded as well).

[jan: fix slot index missing indirection]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:22 +02:00
Avi Kivity 44ea2b1758 KVM: VMX: Move MSR_KERNEL_GS_BASE out of the vmx autoload msr area
Currently MSR_KERNEL_GS_BASE is saved and restored as part of the
guest/host msr reloading.  Since we wish to lazy-restore all the other
msrs, save and reload MSR_KERNEL_GS_BASE explicitly instead of using
the common code.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:21 +02:00
Eduardo Habkost fa40052ca0 KVM: VMX: Use macros instead of hex value on cr0 initialization
This should have no effect, it is just to make the code clearer.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:21 +02:00
Marcelo Tosatti 9fb41ba896 KVM: VMX: fix handle_pause declaration
There's no kvm_run argument anymore.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:18 +02:00
Zhai, Edwin 4b8d54f972 KVM: VMX: Add support for Pause-Loop Exiting
New NHM processors will support Pause-Loop Exiting by adding 2 VM-execution
control fields:
PLE_Gap    - upper bound on the amount of time between two successive
             executions of PAUSE in a loop.
PLE_Window - upper bound on the amount of time a guest is allowed to execute in
             a PAUSE loop

If the time, between this execution of PAUSE and previous one, exceeds the
PLE_Gap, processor consider this PAUSE belongs to a new loop.
Otherwise, processor determins the the total execution time of this loop(since
1st PAUSE in this loop), and triggers a VM exit if total time exceeds the
PLE_Window.
* Refer SDM volume 3b section 21.6.13 & 22.1.3.

Pause-Loop Exiting can be used to detect Lock-Holder Preemption, where one VP
is sched-out after hold a spinlock, then other VPs for same lock are sched-in
to waste the CPU time.

Our tests indicate that most spinlocks are held for less than 212 cycles.
Performance tests show that with 2X LP over-commitment we can get +2% perf
improvement for kernel build(Even more perf gain with more LPs).

Signed-off-by: Zhai Edwin <edwin.zhai@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:17 +02:00
Jan Kiszka 355be0b930 KVM: x86: Refactor guest debug IOCTL handling
Much of so far vendor-specific code for setting up guest debug can
actually be handled by the generic code. This also fixes a minor deficit
in the SVM part /wrt processing KVM_GUESTDBG_ENABLE.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:14 +02:00
Zachary Amsden 3230bb4707 KVM: Fix hotplug of CPUs
Both VMX and SVM require per-cpu memory allocation, which is done at module
init time, for only online cpus.

Backend was not allocating enough structure for all possible CPUs, so
new CPUs coming online could not be hardware enabled.

Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:13 +02:00
Alexander Graf 10474ae894 KVM: Activate Virtualization On Demand
X86 CPUs need to have some magic happening to enable the virtualization
extensions on them. This magic can result in unpleasant results for
users, like blocking other VMMs from working (vmx) or using invalid TLB
entries (svm).

Currently KVM activates virtualization when the respective kernel module
is loaded. This blocks us from autoloading KVM modules without breaking
other VMMs.

To circumvent this problem at least a bit, this patch introduces on
demand activation of virtualization. This means, that instead
virtualization is enabled on creation of the first virtual machine
and disabled on destruction of the last one.

So using this, KVM can be easily autoloaded, while keeping other
hypervisors usable.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:10 +02:00
Mohammed Gamal 80ced186d1 KVM: VMX: Enhance invalid guest state emulation
- Change returned handle_invalid_guest_state() to return relevant exit codes
- Move triggering the emulation from vmx_vcpu_run() to vmx_handle_exit()
- Return to userspace instead of repeatedly trying to emulate instructions that have already failed

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-12-03 09:32:09 +02:00
Avi Kivity 851ba6922a KVM: Don't pass kvm_run arguments
They're just copies of vcpu->run, which is readily accessible.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:06 +02:00
Marcelo Tosatti eb5109e311 KVM: VMX: flush TLB with INVEPT on cpu migration
It is possible that stale EPTP-tagged mappings are used, if a
vcpu migrates to a different pcpu.

Set KVM_REQ_TLB_FLUSH in vmx_vcpu_load, when switching pcpus, which
will invalidate both VPID and EPT mappings on the next vm-entry.

Cc: stable@kernel.org
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-10-04 13:57:24 +02:00
Avi Kivity 0a79b00952 KVM: VMX: Check cpl before emulating debug register access
Debug registers may only be accessed from cpl 0.  Unfortunately, vmx will
code to emulate the instruction even though it was issued from guest
userspace, possibly leading to an unexpected trap later.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 18:11:10 +03:00
Gleb Natapov 542423b0dd KVM: VMX: call vmx_load_host_state() only if msr is cached
No need to call it before each kvm_(set|get)_msr_common()

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 18:11:07 +03:00
Avi Kivity e8a48342e9 KVM: VMX: Conditionally reload debug register 6
Only reload debug register 6 if we're running with the guest's
debug registers.  Saves around 150 cycles from the guest lightweight
exit path.

dr6 contains a couple of bits that are updated on #DB, so intercept
that unconditionally and update those bits then.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 18:11:06 +03:00
Gleb Natapov 5fff7d270b KVM: VMX: Fix cr8 exiting control clobbering by EPT
Don't call adjust_vmx_controls() two times for the same control.
It restores options that were dropped earlier.  This loses us the cr8
exit control, which causes a massive performance regression Windows x64.

Cc: stable@kernel.org
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 10:46:57 +03:00
Sheng Yang 95eb84a758 KVM: VMX: Fix EPT with WP bit change during paging
QNX update WP bit when paging enabled, which is not covered yet. This one fix
QNX boot with EPT.

Cc: stable@kernel.org
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 10:46:53 +03:00
Avi Kivity 345dcaa8fd KVM: VMX: Adjust rflags if in real mode emulation
We set rflags.vm86 when virtualizing real mode to do through vm8086 mode;
so we need to take it out again when reading rflags.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 10:46:43 +03:00
Roel Kluin 3a34a8810b KVM: fix EFER read buffer overflow
Check whether index is within bounds before grabbing the element.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:21 +03:00
Avi Kivity eab4b8aa34 KVM: VMX: Optimize vmx_get_cpl()
Instead of calling vmx_get_segment() (which reads a whole bunch of
vmcs fields), read only the cs selector which contains the cpl.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:21 +03:00
Joerg Roedel 344f414fa0 KVM: report 1GB page support to userspace
If userspace knows that the kernel part supports 1GB pages it can enable
the corresponding cpuid bit so that guests actually use GB pages.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:19 +03:00
Jan Kiszka 7f582ab6d8 KVM: VMX: Avoid to return ENOTSUPP to userland
Choose some allowed error values for the cases VMX returned ENOTSUPP so
far as these values could be returned by the KVM_RUN IOCTL.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 08:33:17 +03:00
Sheng Yang b927a3cec0 KVM: VMX: Introduce KVM_SET_IDENTITY_MAP_ADDR ioctl
Now KVM allow guest to modify guest's physical address of EPT's identity mapping page.

(change from v1, discard unnecessary check, change ioctl to accept parameter
address rather than value)

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-09-10 08:33:16 +03:00
Marcelo Tosatti 229456fc34 KVM: convert custom marker based tracing to event traces
This allows use of the powerful ftrace infrastructure.

See Documentation/trace/ for usage information.

[avi, stephen: various build fixes]
[sheng: fix control register breakage]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:59 +03:00
Avi Kivity d3edefc003 KVM: VMX: Only reload guest cr2 if different from host cr2
cr2 changes only rarely, and writing it is expensive.  Avoid the costly cr2
writes by checking if it does not already hold the desired value.

Shaves 70 cycles off the vmexit latency.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:57 +03:00
Marcelo Tosatti 54dee9933e KVM: VMX: conditionally disable 2M pages
Disable usage of 2M pages if VMX_EPT_2MB_PAGE_BIT (bit 16) is clear
in MSR_IA32_VMX_EPT_VPID_CAP and EPT is enabled.

[avi: s/largepages_disabled/largepages_enabled/ to avoid negative logic]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:56 +03:00
Marcelo Tosatti 68f89400bc KVM: VMX: EPT misconfiguration handler
Handler for EPT misconfiguration which checks for valid state
in the shadow pagetables, printing the spte on each level.

The separate WARN_ONs are useful for kerneloops.org.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:56 +03:00
Marcelo Tosatti e799794e02 KVM: VMX: more MSR_IA32_VMX_EPT_VPID_CAP capability bits
Required for EPT misconfiguration handler.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:55 +03:00
Andre Przywara 71db602322 KVM: Move performance counter MSR access interception to generic x86 path
The performance counter MSRs are different for AMD and Intel CPUs and they
are chosen mainly by the CPUID vendor string. This patch catches writes to
all addresses (regardless of VMX/SVM path) and handles them in the generic
MSR handler routine. Writing a 0 into the event select register is something
we perfectly emulate ;-), so don't print out a warning to dmesg in this
case.
This fixes booting a 64bit Windows guest with an AMD CPUID on an Intel host.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:54 +03:00
Gleb Natapov c5af89b68a KVM: Introduce kvm_vcpu_is_bsp() function.
Use it instead of open code "vcpu_id zero is BSP" assumption.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:51 +03:00
Avi Kivity 7ffd92c53c KVM: VMX: Move rmode structure to vmx-specific code
rmode is only used in vmx, so move it to vmx.c

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:50 +03:00
Nitin A Kamble 3a624e29c7 KVM: VMX: Support Unrestricted Guest feature
"Unrestricted Guest" feature is added in the VMX specification.
Intel Westmere and onwards processors will support this feature.

    It allows kvm guests to run real mode and unpaged mode
code natively in the VMX mode when EPT is turned on. With the
unrestricted guest there is no need to emulate the guest real mode code
in the vm86 container or in the emulator. Also the guest big real mode
code works like native.

  The attached patch enhances KVM to use the unrestricted guest feature
if available on the processor. It also adds a new kernel/module
parameter to disable the unrestricted guest feature at the boot time.

Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:49 +03:00
Avi Kivity 596ae89565 KVM: VMX: Fix reporting of unhandled EPT violations
Instead of returning -ENOTSUPP, exit normally but indicate the hardware
exit reason.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:46 +03:00
Avi Kivity 6de4f3ada4 KVM: Cache pdptrs
Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx,
guest memory access on svm) extract them on demand.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:46 +03:00
Avi Kivity 8f5d549f02 KVM: VMX: Simplify pdptr and cr3 management
Instead of reading the PDPTRs from memory after every exit (which is slow
and wrong, as the PDPTRs are stored on the cpu), sync the PDPTRs from
memory to the VMCS before entry, and from the VMCS to memory after exit.
Do the same for cr3.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:46 +03:00
Avi Kivity 2d84e993a8 KVM: VMX: Avoid duplicate ept tlb flush when setting cr3
vmx_set_cr3() will call vmx_tlb_flush(), which will flush the ept context.
So there is no need to call ept_sync_context() explicitly.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:46 +03:00
Gleb Natapov 787ff73637 KVM: Drop interrupt shadow when single stepping should be done only on VMX
The problem exists only on VMX. Also currently we skip this step if
there is pending exception. The patch fixes this too.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:41 +03:00
Jaswinder Singh Rajput af24a4e4ae KVM: Replace MSR_IA32_TIME_STAMP_COUNTER with MSR_IA32_TSC of msr-index.h
Use standard msr-index.h's MSR declaration.

MSR_IA32_TSC is better than MSR_IA32_TIME_STAMP_COUNTER as it also solves
80 column issue.

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:38 +03:00
Gleb Natapov ae0bb3e011 KVM: VMX: Properly handle software interrupt re-injection in real mode
When reinjecting a software interrupt or exception, use the correct
instruction length provided by the hardware instead of a hardcoded 1.

Fixes problems running the suse 9.1 livecd boot loader.

Problem introduced by commit f0a3602c20 ("KVM: Move interrupt injection
logic to x86.c").

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:32:38 +03:00
Jan Kiszka 263799a361 KVM: VMX: Fix locking imbalance on emulation failure
We have to disable preemption and IRQs on every exit from
handle_invalid_guest_state, otherwise we generate at least a
preempt_disable imbalance.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-05 13:59:45 +03:00
Jan Kiszka 34f0c1ad27 KVM: VMX: Fix locking order in handle_invalid_guest_state
Release and re-acquire preemption and IRQ lock in the same order as
vcpu_enter_guest does.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-08-05 13:59:44 +03:00
Avi Kivity e3c7cb6ad7 KVM: VMX: Handle vmx instruction vmexits
IF a guest tries to use vmx instructions, inject a #UD to let it know the
instruction is not implemented, rather than crashing.

This prevents guest userspace from crashing the guest kernel.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-28 14:10:31 +03:00
Mel Gorman 6484eb3e2a page allocator: do not check NUMA node ID when the caller knows the node is valid
Callers of alloc_pages_node() can optionally specify -1 as a node to mean
"allocate from the current node".  However, a number of the callers in
fast paths know for a fact their node is valid.  To avoid a comparison and
branch, this patch adds alloc_pages_exact_node() that only checks the nid
with VM_BUG_ON().  Callers that know their node is valid are then
converted.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul Mundt <lethal@linux-sh.org>	[for the SLOB NUMA bits]
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:32 -07:00
Andi Kleen a0861c02a9 KVM: Add VT-x machine check support
VT-x needs an explicit MC vector intercept to handle machine checks in the
hyper visor.

It also has a special option to catch machine checks that happen
during VT entry.

Do these interceptions and forward them to the Linux machine check
handler. Make it always look like user space is interrupted because
the machine check handler treats kernel/user space differently.

Thanks to Jiang Yunhong for help and testing.

Cc: stable@kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 12:27:08 +03:00