Commit Graph

290 Commits

Author SHA1 Message Date
Avi Kivity
7cfa4b0a43 Revert "KVM: Avoid useless memory write when possible"
This reverts commit a3c870bdce.  While it
does save useless updates, it (probably) defeats the fork detector, causing
a massive performance loss.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:30:56 +03:00
Rusty Russell
5e58cfe41c KVM: Fix unlikely kvm_create vs decache_vcpus_on_cpu race
We add the kvm to the vm_list before initializing the vcpu mutexes,
which can be mutex_trylock()'ed by decache_vcpus_on_cpu().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:29:34 +03:00
Avi Kivity
b0fcd903e6 KVM: Correctly handle writes crossing a page boundary
Writes that are contiguous in virtual memory may not be contiguous in
physical memory; so split writes that straddle a page boundary.

Thanks to Aurelien for reporting the bug, patient testing, and a fix
to this very patch.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-25 14:29:17 +03:00
Avi Kivity
77668791d9 KVM: Require CONFIG_ANON_INODES
Found by Sebastian Siewior and randconfig.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-22 11:13:59 -07:00
Avi Kivity
c4d198d518 KVM: MMU: Fix cleaning up the shadow page allocation cache
__free_page() wants a struct page, not a virtual address.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-20 23:48:47 -07:00
Avi Kivity
c1158e63df KVM: MMU: Fix oopses with SLUB
The kvm mmu uses page->private on shadow page tables; so does slub, and
an oops result.  Fix by allocating regular pages for shadows instead of
using slub.

Tested-by: S.Çağlar Onur <caglar@pardus.org.tr>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-20 20:23:59 +03:00
Avi Kivity
35f3f28613 KVM: x86 emulator: implement rdmsr and wrmsr
Allow real-mode emulation of rdmsr and wrmsr.  This allows smp Windows to
boot, presumably for its sipi trampoline.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-20 20:16:29 +03:00
Avi Kivity
90cb0529dd KVM: Fix memory slot management functions for guest smp
The memory slot management functions were oriented against vcpu 0, where
they should be kvm-wide.  This causes hangs starting X on guest smp.

Fix by making the functions (and resultant tail in the mmu) non-vcpu-specific.
Unfortunately this reduces the efficiency of the mmu object cache a bit.  We
may have to revisit this later.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-20 20:16:29 +03:00
Avi Kivity
d55e2cb201 KVM: MMU: Store nx bit for large page shadows
We need to distinguish between large page shadows which have the nx bit set
and those which don't.  The problem shows up when booting a newer smp Linux
kernel, where the trampoline page (which is in real mode, which uses the
same shadow pages as large pages) is using the same mapping as a kernel data
page, which is mapped using nx, causing kvm to spin on that page.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-20 20:16:29 +03:00
Paul Mundt
20c2df83d2 mm: Remove slab destructors from kmem_cache_create().
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-20 10:11:58 +09:00
Avi Kivity
2d9ce177e6 i386: Allow KVM on i386 nonpae
Currently, CONFIG_X86_CMPXCHG64 both enables boot-time checking of
the cmpxchg64b feature and enables compilation of the set_64bit() family.
Since the option is dependent on PAE, and since KVM depends on set_64bit(),
this effectively disables KVM on i386 nopae.

Simplify by removing the config option altogether: the boot check is made
dependent on CONFIG_X86_PAE directly, and the set_64bit() family is exposed
without constraints.  It is up to users to check for the feature flag (KVM
does not as virtualiation extensions imply its existence).

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 14:37:05 -07:00
Avi Kivity
cec9ad279b KVM: Use CPU_DYING for disabling virtualization
Only at the CPU_DYING stage can we be sure that no user process will
be scheduled onto the cpu and oops when trying to use virtualization
extensions.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:51 +03:00
Avi Kivity
4267c41a45 KVM: Tune hotplug/suspend IPIs
The hotplug IPIs can be called from the cpu on which we are currently
running on, so use on_cpu().  Similarly, drop on_each_cpu() for the
suspend/resume callbacks, as we're in atomic context here and only one
cpu is up anyway.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:51 +03:00
Avi Kivity
1b6c016818 KVM: Keep track of which cpus have virtualization enabled
By keeping track of which cpus have virtualization enabled, we
prevent double-enable or double-disable during hotplug, which is a
very fatal oops.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:51 +03:00
Avi Kivity
e495606dd0 KVM: Clean up #includes
Remove unnecessary ones, and rearange the remaining in the standard order.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:49 +03:00
Avi Kivity
d6d2816849 KVM: Remove kvmfs in favor of the anonymous inodes source
kvm uses a pseudo filesystem, kvmfs, to generate inodes, a job that the
new anonymous inodes source does much better.

Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:49 +03:00
Joerg Roedel
6031a61c2e KVM: SVM: Reliably detect if SVM was disabled by BIOS
This patch adds an implementation to the svm is_disabled function to
detect reliably if the BIOS disabled the SVM feature in the CPU. This
fixes the issues with kernel panics when loading the kvm-amd module on
machines where SVM is available but disabled.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:49 +03:00
Avi Kivity
796fd1b23e KVM: VMX: Remove unnecessary code in vmx_tlb_flush()
A vmexit implicitly flushes the tlb; the code is bogus.

Noted by Shaohua Li.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:49 +03:00
Shaohua Li
88a97f0b2f KVM: MMU: Fix Wrong tlb flush order
Need to flush the tlb after updating a pte, not before.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Avi Kivity
75880a0112 KVM: VMX: Reinitialize the real-mode tss when entering real mode
Protected mode code may have corrupted the real-mode tss, so re-initialize
it when switching to real mode.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Luca Tettamanti
a3c870bdce KVM: Avoid useless memory write when possible
When writing to normal memory and the memory area is unchanged the write
can be safely skipped, avoiding the costly kvm_mmu_pte_write.

Signed-Off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Luca Tettamanti
02c03a326a KVM: Fix x86 emulator writeback
When the old value and new one are the same the emulator skips the
write; this is undesirable when the destination is a MMIO area and the
write shall be performed regardless of the previous value. This
optimization breaks e.g. a Linux guest APIC compiled without
X86_GOOD_APIC.

Remove the check and perform the writeback stage in the emulation unless
it's explicitly disabled (currently push and some 2 bytes instructions
may disable the writeback).

Signed-Off-By: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Eddie Dong
74906345ff KVM: Add support for in-kernel pio handlers
Useful for the PIC and PIT.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Gregory Haskins
ff1dc7942b KVM: VMX: Fix interrupt checking on lightweight exit
With kernel-injected interrupts, we need to check for interrupts on
lightweight exits too.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:48 +03:00
Gregory Haskins
2eeb2e94eb KVM: Adds support for in-kernel mmio handlers
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Nitin A Kamble
d9413cd757 KVM: Implement emulation of instruction "ret" (opcode 0xc3)
Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Nitin A Kamble
7f0aaee07b KVM: Implement emulation of "pop reg" instruction (opcode 0x58-0x5f)
For use in real mode.

Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Avi Kivity
7700270ee3 KVM: VMX: Ensure vcpu time stamp counter is monotonous
If the time stamp counter goes backwards, a guest delay loop can become
infinite.  This can happen if a vcpu is migrated to another cpu, where
the counter has a lower value than the first cpu.

Since we're doing an IPI to the first cpu anyway, we can use that to pick
up the old tsc, and use that to calculate the adjustment we need to make
to the tsc offset.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Avi Kivity
94cea1bb9d KVM: Initialize the BSP bit in the APIC_BASE msr correctly
Needs to be set on vcpu 0 only.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Shani Moideen
a3870c4789 KVM: VMX: Replace memset(<addr>, 0, PAGESIZE) with clear_page(<addr>)
Signed-off-by: Shani Moideen <shani.moideen@wipro.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:47 +03:00
Shani Moideen
129ee910df KVM: SVM: Replace memset(<addr>, 0, PAGESIZE) with clear_page(<addr>)
Signed-off-by: Shani Moideen <shani.moideen@wipro.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
d9e368d612 KVM: Flush remote tlbs when reducing shadow pte permissions
When a vcpu causes a shadow tlb entry to have reduced permissions, it
must also clear the tlb on remote vcpus.  We do that by:

- setting a bit on the vcpu that requests a tlb flush before the next entry
- if the vcpu is currently executing, we send an ipi to make sure it
  exits before we continue

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
39c3b86e5c KVM: Keep an upper bound of initialized vcpus
That way, we don't need to loop for KVM_MAX_VCPUS for a single vcpu
vm.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
72d6e5a08a KVM: Emulate hlt on real mode for Intel
This has two use cases: the bios can't boot from disk, and guest smp
bootstrap.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
d3bef15f84 KVM: Move duplicate halt handling code into kvm_main.c
Will soon have a thid user.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
ef9254df0b KVM: Enable guest smp
As we don't support guest tlb shootdown yet, this is only reliable
for real-mode guests.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:46 +03:00
Avi Kivity
120e9a453b KVM: Fix adding an smp virtual machine to the vm list
If we add the vm once per vcpu, we corrupt the list if the guest has
multiple vcpus.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Avi Kivity
7b53aa5650 KVM: Fix vcpu freeing for guest smp
A vcpu can pin up to four mmu shadow pages, which means the freeing
loop will never terminate.  Fix by first unpinning shadow pages on
all vcpus, then freeing shadow pages.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Nguyen Anh Quynh
313899477f KVM: Remove unnecessary initialization and checks in mark_page_dirty()
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Robert P. J. Day
50a3485c59 KVM: Replace C code with call to ARRAY_SIZE() macro.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Avi Kivity
17c3ba9d37 KVM: Lazy guest cr3 switching
Switch guest paging context may require us to allocate memory, which
might fail.  Instead of wiring up error paths everywhere, make context
switching lazy and actually do the switch before the next guest entry,
where we can return an error if allocation fails.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Avi Kivity
bd2b2baa5c KVM: MMU: Remove unused large page marker
This has not been used for some time, as the same information is available
in the page header.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:45 +03:00
Avi Kivity
b64b3763a5 KVM: MMU: Don't cache guest access bits in the shadow page table
This was once used to avoid accessing the guest pte when upgrading
the shadow pte from read-only to read-write.  But usually we need
to set the guest pte dirty or accessed bits anyway, so this wasn't
really exploited.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:44 +03:00
Avi Kivity
fd97dc516c KVM: MMU: Simpify accessed/dirty/present/nx bit handling
Always set the accessed and dirty bit (since having them cleared causes
a read-modify-write cycle), always set the present bit, and copy the
nx bit from the guest.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:44 +03:00
Avi Kivity
4436d46621 KVM: MMU: Remove cr0.wp tricks
No longer needed as we do everything in one place.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:44 +03:00
Avi Kivity
e663ee64ae KVM: MMU: Make setting shadow ptes atomic on i386
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:44 +03:00
Avi Kivity
0d551bb698 KVM: Make shadow pte updates atomic
With guest smp, a second vcpu might see partial updates when the first
vcpu services a page fault.  So delay all updates until we have figured
out what the pte should look like.

Note that on i386, this is still not completely atomic as a 64-bit write
will be split into two on a 32-bit machine.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:44 +03:00
Avi Kivity
a18de5a403 KVM: Move shadow pte modifications from set_pte/set_pde to set_pde_common()
We want all shadow pte modifications in one place.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:44 +03:00
Avi Kivity
97a0a01ea9 KVM: MMU: Fold fix_write_pf() into set_pte_common()
This prevents some work from being performed twice, and, more importantly,
reduces the number of places where we modify shadow ptes.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:43 +03:00
Avi Kivity
63b1ad24d2 KVM: MMU: Fold fix_read_pf() into set_pte_common()
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:43 +03:00