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path: root/drivers/kvm
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2007-05-03KVM: SVM: Only save/restore MSRs when neededAnthony Liguori
We only have to save/restore MSR_GS_BASE on every VMEXIT. The rest can be saved/restored when we leave the VCPU. Since we don't emulate the DEBUGCTL MSRs and the guest cannot write to them, we don't have to worry about saving/restoring them at all. This shaves a whopping 40% off raw vmexit costs on AMD. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: fix an if() conditionAdrian Bunk
It might have worked in this case since PT_PRESENT_MASK is 1, but let's express this correctly. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: VMX: Add lazy FPU support for VTAnthony Liguori
Only save/restore the FPU host state when the guest is actually using the FPU. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: VMX: Properly shadow the CR0 register in the vcpu structAnthony Liguori
Set all of the host mask bits for CR0 so that we can maintain a proper shadow of CR0. This exposes CR0.TS, paving the way for lazy fpu handling. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Don't complain about cpu erratum AA15Avi Kivity
It slows down Windows x64 horribly. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Lazy FPU support for SVMAnthony Liguori
Avoid saving and restoring the guest fpu state on every exit. This shaves ~100 cycles off the guest/host switch. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Allow passing 64-bit values to the emulated read/write APIAvi Kivity
This simplifies the API somewhat (by eliminating the special-case cmpxchg8b on i386). Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Per-vcpu statisticsAvi Kivity
Make the exit statistics per-vcpu instead of global. This gives a 3.5% boost when running one virtual machine per core on my two socket dual core (4 cores total) machine. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: VMX: Avoid unnecessary vcpu_load()/vcpu_put() cyclesYaozu Dong
By checking if a reschedule is needed, we avoid dropping the vcpu. [With changes by me, based on Anthony Liguori's observations] Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: MMU: Avoid heavy ASSERT at non debug mode.Yaozu Dong
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: VMX: Only save/restore MSR_K6_STAR if necessaryAvi Kivity
Intel hosts only support syscall/sysret in long more (and only if efer.sce is enabled), so only reload the related MSR_K6_STAR if the guest will actually be able to use it. This reduces vmexit cost by about 500 cycles (6400 -> 5870) on my setup. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Fold drivers/kvm/kvm_vmx.h into drivers/kvm/vmx.cAvi Kivity
No meat in that file. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: VMX: Don't switch 64-bit msrs for 32-bit guestsAvi Kivity
Some msrs are only used by x86_64 instructions, and are therefore not needed when the guest is legacy mode. By not bothering to switch them, we reduce vmexit latency by 2400 cycles (from about 8800) when running a 32-bt guest on a 64-bit host. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: VMX: Reduce unnecessary saving of host msrsAvi Kivity
THe automatically switched msrs are never changed on the host (with the exception of MSR_KERNEL_GS_BASE) and thus there is no need to save them on every vm entry. This reduces vmexit latency by ~400 cycles on i386 and by ~900 cycles (10%) on x86_64. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Handle guest page faults when emulating mmioAvi Kivity
Usually, guest page faults are detected by the kvm page fault handler, which detects if they are shadow faults, mmio faults, pagetable faults, or normal guest page faults. However, in ceratin circumstances, we can detect a page fault much later. One of these events is the following combination: - A two memory operand instruction (e.g. movsb) is executed. - The first operand is in mmio space (which is the fault reported to kvm) - The second operand is in an ummaped address (e.g. a guest page fault) The Windows 2000 installer does such an access, an promptly hangs. Fix by adding the missing page fault injection on that path. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: SVM: Report hardware exit reason to userspace instead of dmesgAvi Kivity
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Retry sleeping allocation if atomic allocation failsAvi Kivity
This avoids -ENOMEM under memory pressure. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Use slab caches to allocate mmu data structuresAvi Kivity
Better leak detection, statistics, memory use, speed -- goodness all around. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Handle partial pae pdptrAvi Kivity
Some guests (Solaris) do not set up all four pdptrs, but leave some invalid. kvm incorrectly treated these as valid page directories, pinning the wrong pages and causing general confusion. Fix by checking the valid bit of a pae pdpte. This closes sourceforge bug 1698922. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Initialize cr0 to indicate an fpu is presentAvi Kivity
Solaris panics if it sees a cpu with no fpu, and it seems to rely on this bit. Closes sourceforge bug 1698920. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Fix overflow bug in overflow detection codeEric Sesterhenn / Snakebyte
The expression sp - 6 < sp where sp is a u16 is undefined in C since 'sp - 6' is promoted to int, and signed overflow is undefined in C. gcc 4.2 actually warns about it. Replace with a simpler test. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Use kernel-standard typesAvi Kivity
Noted by Joerg Roedel. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: SVM: enable LBRV virtualization if availableJoerg Roedel
This patch enables the virtualization of the last branch record MSRs on SVM if this feature is available in hardware. It also introduces a small and simple check feature for specific SVM extensions. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Add fpu get/set operationsAvi Kivity
These are really helpful when migrating an floating point app to another machine. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Add physical memory aliasing featureAvi Kivity
With this, we can specify that accesses to one physical memory range will be remapped to another. This is useful for the vga window at 0xa0000 which is used as a movable window into the (much larger) framebuffer. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Simply gfn_to_page()Avi Kivity
Mapping a guest page to a host page is a common operation. Currently, one has first to find the memory slot where the page belongs (gfn_to_memslot), then locate the page itself (gfn_to_page()). This is clumsy, and also won't work well with memory aliases. So simplify gfn_to_page() not to require memory slot translation first, and instead do it internally. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Add mmu cache clear functionDor Laor
Functions that play around with the physical memory map need a way to clear mappings to possibly nonexistent or invalid memory. Both the mmu cache and the processor tlb are cleared. Signed-off-by: Dor Laor <dor.laor@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: x86 emulator: fix bit string operations operand sizeAvi Kivity
On x86, bit operations operate on a string of bits that can reside in multiple words. For example, 'btsl %eax, (blah)' will touch the word at blah+4 if %eax is between 32 and 63. The x86 emulator compensates for that by advancing the operand address by (bit offset / BITS_PER_LONG) and truncating the bit offset to the range (0..BITS_PER_LONG-1). This has a side effect of forcing the operand size to 8 bytes on 64-bit hosts. Now, a 32-bit guest goes and fork()s a process. It write protects a stack page at 0xbffff000 using the 'btr' instruction, at offset 0xffc in the page table, with bit offset 1 (for the write permission bit). The emulator now forces the operand size to 8 bytes as previously described, and an innocent page table update turns into a cross-page-boundary write, which is assumed by the mmu code not to be a page table, so it doesn't actually clear the corresponding shadow page table entry. The guest and host permissions are out of sync and guest memory is corrupted soon afterwards, leading to guest failure. Fix by not using BITS_PER_LONG as the word size; instead use the actual operand size, so we get a 32-bit write in that case. Note we still have to teach the mmu to handle cross-page-boundary writes to guest page table; but for now this allows Damn Small Linux 0.4 (2.4.20) to boot. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Remove debug messageAvi Kivity
No longer interesting. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Use list_move()Avi Kivity
Use list_move() where possible. Noticed by Dor Laor. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Remove unused functionMichal Piotrowski
Remove unused function CC drivers/kvm/svm.o drivers/kvm/svm.c:207: warning: ‘inject_db’ defined but not used Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: SVM: Ensure timestamp counter monotonicityAvi Kivity
When a vcpu is migrated from one cpu to another, its timestamp counter may lose its monotonic property if the host has unsynced timestamp counters. This can confuse the guest, sometimes to the point of refusing to boot. As the rdtsc instruction is rather fast on AMD processors (7-10 cycles), we can simply record the last host tsc when we drop the cpu, and adjust the vcpu tsc offset when we detect that we've migrated to a different cpu. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: MMU: Fix hugepage pdes mapping same physical address with different accessAvi Kivity
The kvm mmu keeps a shadow page for hugepage pdes; if several such pdes map the same physical address, they share the same shadow page. This is a fairly common case (kernel mappings on i386 nonpae Linux, for example). However, if the two pdes map the same memory but with different permissions, kvm will happily use the cached shadow page. If the access through the more permissive pde will occur after the access to the strict pde, an endless pagefault loop will be generated and the guest will make no progress. Fix by making the access permissions part of the cache lookup key. The fix allows Xen pae to boot on kvm and run guest domains. Thanks to Jeremy Fitzhardinge for reporting the bug and testing the fix. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: SVM: forbid guest to execute monitor/mwaitJoerg Roedel
This patch forbids the guest to execute monitor/mwait instructions on SVM. This is necessary because the guest can execute these instructions if they are available even if the kvm cpuid doesn't report its existence. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Handle writes to MCG_STATUS msrSergey Kiselev
Some older (~2.6.7) kernels write MCG_STATUS register during kernel boot (mce_clear_all() function, called from mce_init()). It's not currently handled by kvm and will cause it to inject a GPF. Following patch adds a "nop" handler for this. Signed-off-by: Sergey Kiselev <sergey.kiselev@intel.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Remove unused and write-only variablesAvi Kivity
Trivial cleanup. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Don't allow the guest to turn off the cpu cacheAvi Kivity
The cpu cache is a host resource; the guest should not be able to turn it off (even for itself). Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Hack real-mode segments on vmx from KVM_SET_SREGSAvi Kivity
As usual, we need to mangle segment registers when emulating real mode as vm86 has specific constraints. We special case the reset segment base, and set the "access rights" (or descriptor flags) to vm86 comaptible values. This fixes reboot on vmx. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Modify guest segments after potentially switching modesAvi Kivity
The SET_SREGS ioctl modifies both cr0.pe (real mode/protected mode) and guest segment registers. Since segment handling is modified by the mode on Intel procesors, update the segment registers after the mode switch has taken place. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Remove set_cr0_no_modeswitch() arch opAvi Kivity
set_cr0_no_modeswitch() was a hack to avoid corrupting segment registers. As we now cache the protected mode values on entry to real mode, this isn't an issue anymore, and it interferes with reboot (which usually _is_ a modeswitch). Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Workaround vmx inability to virtualize the reset stateAvi Kivity
The reset state has cs.selector == 0xf000 and cs.base == 0xffff0000, which aren't compatible with vm86 mode, which is used for real mode virtualization. When we create a vcpu, we set cs.base to 0xf0000, but if we get there by way of a reset, the values are inconsistent and vmx refuses to enter guest mode. Workaround by detecting the state and munging it appropriately. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: MMU: Remove global pte trackingAvi Kivity
The initial, noncaching, version of the kvm mmu flushed the all nonglobal shadow page table translations (much like a native tlb flush). The new implementation flushes translations only when they change, rendering global pte tracking superfluous. This removes the unused tracking mechanism and storage space. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: MMU: Remove unnecessary check for pdptr accessAvi Kivity
We already special case the pdptr access, so no need to check it again. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Avoid guest virtual addresses in string pio userspace interfaceAvi Kivity
The current string pio interface communicates using guest virtual addresses, relying on userspace to translate addresses and to check permissions. This interface cannot fully support guest smp, as the check needs to take into account two pages at one in case an unaligned string transfer straddles a page boundary. Change the interface not to communicate guest addresses at all; instead use a buffer page (mmaped by userspace) and do transfers there. The kernel manages the virtual to physical translation and can perform the checks atomically by taking the appropriate locks. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Future-proof argument-less ioctlsAvi Kivity
Some ioctls ignore their arguments. By requiring them to be zero now, we allow a nonzero value to have some special meaning in the future. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Allow kernel to select size of mmap() bufferAvi Kivity
This allows us to store offsets in the kernel/user kvm_run area, and be sure that userspace has them mapped. As offsets can be outside the kvm_run struct, userspace has no way of knowing how much to mmap. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Add guest mode signal maskAvi Kivity
Allow a special signal mask to be used while executing in guest mode. This allows signals to be used to interrupt a vcpu without requiring signal delivery to a userspace handler, which is quite expensive. Userspace still receives -EINTR and can get the signal via sigwait(). Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Initialize the apic_base msr on svm tooAvi Kivity
Older userspace didn't care, but newer userspace (with the cpuid changes) does. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Add a special exit reason when exiting due to an interruptAvi Kivity
This is redundant, as we also return -EINTR from the ioctl, but it allows us to examine the exit_reason field on resume without seeing old data. Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-05-03KVM: Fold kvm_run::exit_type into kvm_run::exit_reasonAvi Kivity
Currently, userspace is told about the nature of the last exit from the guest using two fields, exit_type and exit_reason, where exit_type has just two enumerations (and no need for more). So fold exit_type into exit_reason, reducing the complexity of determining what really happened. Signed-off-by: Avi Kivity <avi@qumranet.com>