The PIC code makes little effort to avoid kvm_vcpu_kick(), resulting in
unnecessary guest exits in some conditions.
For example, if the timer interrupt is routed through the IOAPIC, IRR
for IRQ 0 will get set but not cleared, since the APIC is handling the
acks.
This means that everytime an interrupt < 16 is triggered, the priority
logic will find IRQ0 pending and send an IPI to vcpu0 (in case IRQ0 is
not masked, which is Linux's case).
Introduce a new variable isr_ack to represent the IRQ's for which the
guest has been signalled / cleared the ISR. Use it to avoid more than
one IPI per trigger-ack cycle, in addition to the avoidance when ISR is
set in get_priority().
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Allow guest pagetables to go out of sync. Instead of emulating write
accesses to guest pagetables, or unshadowing them, we un-write-protect
the page table and allow the guest to modify it at will. We rely on
invlpg executions to synchronize individual ptes, and will synchronize
the entire pagetable on tlb flushes.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
There is not much point in write protecting large mappings. This
can only happen when a page is shadowed during the window between
is_largepage_backed and mmu_lock acquision. Zap the entry instead, so
the next pagefault will find a shadowed page via is_largepage_backed and
fallback to 4k translations.
Simplifies out of sync shadow.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Harvey Harrison [Tue, 23 Sep 2008 18:01:45 +0000 (11:01 -0700)]
x86: pvclock: fix shadowed variable warning
arch/x86/kernel/pvclock.c:102:6: warning: symbol 'tsc_khz' shadows an earlier one
include/asm/tsc.h:18:21: originally declared here
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Avi Kivity <avi@redhat.com>
In Tukwila processor, VT-i has been enhanced in its
implementation, it is often called VT-i2 techonology.
With VTi-2 support, virtulization performance should be
improved. In this patch, we added the related stuff to
support kvm/ia64 for Tukwila processors.
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
An uniform entry kvm_vps_entry is added for
vps_sync_write/read, vps_resume_handler/guest,
and branches to differnt PAL service according to the offset.
Singed-off-by: Anthony Xu <anthony.xu@intel.com> Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Glauber Costa [Thu, 18 Sep 2008 02:16:59 +0000 (23:16 -0300)]
KVM: Don't destroy vcpu in case vcpu_setup fails
One of vcpu_setup responsibilities is to do mmu initialization.
However, in case we fail in kvm_arch_vcpu_reset, before we get the
chance to init mmu. OTOH, vcpu_destroy will attempt to destroy mmu,
triggering a bug. Keeping track of whether or not mmu is initialized
would unnecessarily complicate things. Rather, we just make return,
making sure any needed uninitialization is done before we return, in
case we fail.
Signed-off-by: Glauber Costa <glommer@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
KVM: don't enter guest after SIPI was received by a CPU
The vcpu should process pending SIPI message before entering guest mode again.
kvm_arch_vcpu_runnable() returns true if the vcpu is in SIPI state, so
we can't call it here.
Signed-off-by: Gleb Natapov <gleb@qumranet.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Convert gfn_to_pfn to use get_user_pages_fast, which can do lockless
pagetable lookups on x86. Kernel compilation on 4-way guest is 3.7%
faster on VMX.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
kvm_vm_fault is invoked with mmap_sem held in read mode. Since gfn_to_page
will be converted to get_user_pages_fast, which requires this lock NOT
to be held, switch to opencoded get_user_pages.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Amit Shah [Tue, 16 Sep 2008 15:04:28 +0000 (18:04 +0300)]
KVM: Device Assignment: Free device structures if IRQ allocation fails
When an IRQ allocation fails, we free up the device structures and
disable the device so that we can unregister the device in the
userspace and not expose it to the guest at all.
Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Based on a patch by: Kay, Allen M <allen.m.kay@intel.com>
This patch enables PCI device assignment based on VT-d support.
When a device is assigned to the guest, the guest memory is pinned and
the mapping is updated in the VT-d IOMMU.
[Amit: Expose KVM_CAP_IOMMU so we can check if an IOMMU is present
and also control enable/disable from userspace]
Signed-off-by: Kay, Allen M <allen.m.kay@intel.com> Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Amit Shah <amit.shah@qumranet.com> Acked-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Kay, Allen M [Tue, 9 Sep 2008 15:37:29 +0000 (18:37 +0300)]
VT-d: Changes to support KVM
This patch extends the VT-d driver to support KVM
[Ben: fixed memory pinning]
[avi: move dma_remapping.h as well]
Signed-off-by: Kay, Allen M <allen.m.kay@intel.com> Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Amit Shah <amit.shah@qumranet.com> Acked-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Add DstAcc operand type. That means that there are 4 bits now for
DstMask.
"In the good old days cpus would have only one register that was able to
fully participate in arithmetic operations, typically called A for
Accumulator. The x86 retains this tradition by having special, shorter
encodings for the A register (like the cmp opcode), and even some
instructions that only operate on A (like mul).
SrcAcc and DstAcc would accommodate these instructions by decoding A
into the corresponding 'struct operand'."
-- Avi Kivity
Signed-off-by: Guillaume Thouvenin <guillaume.thouvenin@ext.bull.net> Signed-off-by: Avi Kivity <avi@qumranet.com>
Avi Kivity [Thu, 11 Sep 2008 16:47:13 +0000 (19:47 +0300)]
KVM: x86 emulator: fix jmp r/m64 instruction
jmp r/m64 doesn't require the rex.w prefix to indicate the operand size
is 64 bits. Set the Stack attribute (even though it doesn't involve the
stack, really) to indicate this.
Offline or uninitialized vcpu's can be executed if requested to perform
userspace work.
Follow Avi's suggestion to handle halted vcpu's in the main loop,
simplifying kvm_emulate_halt(). Introduce a new vcpu->requests bit to
indicate events that promote state from halted to running.
Also standardize vcpu wake sites.
Signed-off-by: Marcelo Tosatti <mtosatti <at> redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Sheng Yang [Mon, 1 Sep 2008 11:41:20 +0000 (19:41 +0800)]
KVM: MMU: Modify kvm_shadow_walk.entry to accept u64 addr
EPT is 4 level by default in 32pae(48 bits), but the addr parameter
of kvm_shadow_walk->entry() only accept unsigned long as virtual
address, which is 32bit in 32pae. This result in SHADOW_PT_INDEX()
overflow when try to fetch level 4 index.
Fix it by extend kvm_shadow_walk->entry() to accept 64bit addr in
parameter.
Signed-off-by: Sheng Yang <sheng.yang@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Heiko Carstens pointed out, that its safer to activate working facilities
instead of disabling problematic facilities. The new code uses the host
facility bits and masks it with known good ones.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Joerg Roedel [Fri, 29 Aug 2008 09:52:07 +0000 (11:52 +0200)]
KVM: add MC5_MISC msr read support
Currently KVM implements MC0-MC4_MISC read support. When booting Linux this
results in KVM warnings in the kernel log when the guest tries to read
MC5_MISC. Fix this warnings with this patch.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Avi Kivity [Wed, 27 Aug 2008 17:01:04 +0000 (20:01 +0300)]
KVM: MMU: Fix setting the accessed bit on non-speculative sptes
The accessed bit was accidentally turned on in a random flag word, rather
than, the spte itself, which was lucky, since it used the non-EPT compatible
PT_ACCESSED_MASK.
Fix by turning the bit on in the spte and changing it to use the portable
accessed mask.
Avi Kivity [Tue, 26 Aug 2008 14:31:31 +0000 (17:31 +0300)]
KVM: Don't call get_user_pages(.force = 1)
This is esoteric and only needed to break COW on MAP_SHARED mappings. Since
KVM no longer does these sorts of mappings, breaking COW on them is no longer
necessary.
Avi Kivity [Fri, 22 Aug 2008 16:24:38 +0000 (19:24 +0300)]
KVM: MMU: Add generic shadow walker
We currently walk the shadow page tables in two places: direct map (for
real mode and two dimensional paging) and paging mode shadow. Since we
anticipate requiring a third walk (for invlpg), it makes sense to have
a generic facility for shadow walk.
This patch adds such a shadow walker, walks the page tables and calls a
method for every spte encountered. The method can examine the spte,
modify it, or even instantiate it. The walk can be aborted by returning
nonzero from the method.
Harvey Harrison [Mon, 11 Aug 2008 23:54:20 +0000 (16:54 -0700)]
KVM: make irq ack notifier functions static
sparse says:
arch/x86/kvm/x86.c:107:32: warning: symbol 'kvm_find_assigned_dev' was not declared. Should it be static?
arch/x86/kvm/i8254.c:225:6: warning: symbol 'kvm_pit_ack_irq' was not declared. Should it be static?
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Avi Kivity <avi@qumranet.com>
Mohammed Gamal [Sun, 17 Aug 2008 13:39:48 +0000 (16:39 +0300)]
KVM: VMX: Add module parameter and emulation flag.
The patch adds the module parameter required to enable emulating invalid
guest state, as well as the emulation_required flag used to drive
emulation whenever needed.
Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Marcelo Tosatti [Thu, 14 Aug 2008 23:53:25 +0000 (20:53 -0300)]
KVM: fix i8259 reset irq acking
The irq ack during pic reset has three problems:
- Ignores slave/master PIC, using gsi 0-8 for both.
- Generates an ACK even if the APIC is in control.
- Depends upon IMR being clear, which is broken if the irq was masked
at the time it was generated.
The last one causes the BIOS to hang after the first reboot of
Windows installation, since PIT interrupts stop.
[avi: fix check whether pic interrupts are seen by cpu]
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Dave Hansen [Mon, 11 Aug 2008 17:01:49 +0000 (10:01 -0700)]
KVM: Reduce stack usage in kvm_pv_mmu_op()
We're in a hot path. We can't use kmalloc() because
it might impact performance. So, we just stick the buffer that
we need into the kvm_vcpu_arch structure. This is used very
often, so it is not really a waste.
We also have to move the buffer structure's definition to the
arch-specific x86 kvm header.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Dave Hansen [Mon, 11 Aug 2008 17:01:45 +0000 (10:01 -0700)]
KVM: Reduce kvm stack usage in kvm_arch_vm_ioctl()
On my machine with gcc 3.4, kvm uses ~2k of stack in a few
select functions. This is mostly because gcc fails to
notice that the different case: statements could have their
stack usage combined. It overflows very nicely if interrupts
happen during one of these large uses.
This patch uses two methods for reducing stack usage.
1. dynamically allocate large objects instead of putting
on the stack.
2. Use a union{} member for all of the case variables. This
tricks gcc into combining them all into a single stack
allocation. (There's also a comment on this)
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Based on a patch from: Amit Shah <amit.shah@qumranet.com>
This patch adds support for handling PCI devices that are assigned to
the guest.
The device to be assigned to the guest is registered in the host kernel
and interrupt delivery is handled. If a device is already assigned, or
the device driver for it is still loaded on the host, the device
assignment is failed by conveying a -EBUSY reply to the userspace.
Devices that share their interrupt line are not supported at the moment.
By itself, this patch will not make devices work within the guest.
The VT-d extension is required to enable the device to perform DMA.
Another alternative is PVDMA.
Signed-off-by: Amit Shah <amit.shah@qumranet.com> Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com> Signed-off-by: Weidong Han <weidong.han@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Userspace may specify memory slots that are backed by mmio pages rather than
normal RAM. In some cases it is not enough to identify these mmio pages
by pfn_valid(). This patch adds checking the PageReserved as well.
Glauber Costa [Mon, 28 Jul 2008 14:47:53 +0000 (11:47 -0300)]
x86: KVM guest: use paravirt function to calculate cpu khz
We're currently facing timing problems in guests that do
calibration under heavy load, and then the load vanishes.
This means we'll have a much lower lpj than we actually should,
and delays end up taking less time than they should, which is a
nasty bug.
Solution is to pass on the lpj value from host to guest, and have it
preset.
Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
The PIT injection logic is problematic under the following cases:
1) If there is a higher priority vector to be delivered by the time
kvm_pit_timer_intr_post is invoked ps->inject_pending won't be set.
This opens the possibility for missing many PIT event injections (say if
guest executes hlt at this point).
2) ps->inject_pending is racy with more than two vcpus. Since there's no locking
around read/dec of pt->pending, two vcpu's can inject two interrupts for a single
pt->pending count.
Fix 1 by using an irq ack notifier: only reinject when the previous irq
has been acked. Fix 2 with appropriate locking around manipulation of
pending count and irq_ack by the injection / ack paths.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
KVM: powerpc: Map guest userspace with TID=0 mappings
When we use TID=N userspace mappings, we must ensure that kernel mappings have
been destroyed when entering userspace. Using TID=1/TID=0 for kernel/user
mappings and running userspace with PID=0 means that userspace can't access the
kernel mappings, but the kernel can directly access userspace.
The net is that we don't need to flush the TLB on privilege switches, but we do
on guest context switches (which are far more infrequent). Guest boot time
performance improvement: about 30%.
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
KVM: ppc: Write only modified shadow entries into the TLB on exit
Track which TLB entries need to be written, instead of overwriting everything
below the high water mark. Typically only a single guest TLB entry will be
modified in a single exit.
Guest boot time performance improvement: about 15%.
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
We're saving the host TLB state to memory on every exit, but never using it.
Originally I had thought that we'd want to restore host TLB for heavyweight
exits, but that could actually hurt when context switching to an unrelated host
process (i.e. not qemu).
Since this decreases the performance penalty of all exits, this patch improves
guest boot time by about 15%.
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Alexander Graf [Tue, 22 Jul 2008 06:00:45 +0000 (08:00 +0200)]
KVM: Ignore DEBUGCTL MSRs with no effect
Netware writes to DEBUGCTL and reads from the DEBUGCTL and LAST*IP MSRs
without further checks and is really confused to receive a #GP during that.
To make it happy we should just make them stubs, which is exactly what SVM
already does.
Writes to DEBUGCTL that are vendor-specific are resembled to behave as if the
virtual CPU does not know them.
Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@qumranet.com>
projects / linux-beck.git / log