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2010-05-17KVM: x86: Push potential exception error code on task switchesJan Kiszka1-0/+1
When a fault triggers a task switch, the error code, if existent, has to be pushed on the new task's stack. Implement the missing bits. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-05-17KVM: SVM: implement NEXTRIPsave SVM featureAndre Przywara1-1/+3
On SVM we set the instruction length of skipped instructions to hard-coded, well known values, which could be wrong when (bogus, but valid) prefixes (REX, segment override) are used. Newer AMD processors (Fam10h 45nm and better, aka. PhenomII or AthlonII) have an explicit NEXTRIP field in the VMCB containing the desired information. Since it is cheap to do so, we use this field to override the guessed value on newer processors. A fix for older CPUs would be rather expensive, as it would require to fetch and partially decode the instruction. As the problem is not a security issue and needs special, handcrafted code to trigger (no compiler will ever generate such code), I omit a fix for older CPUs. If someone is interested, I have both a patch for these CPUs as well as demo code triggering this issue: It segfaults under KVM, but runs perfectly on native Linux. Signed-off-by: Andre Przywara <andre.przywara@amd.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-04-25KVM: SVM: Implement emulation of vm_cr msrJoerg Roedel1-0/+4
This patch implements the emulation of the vm_cr msr for nested svm. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2010-03-01KVM: SVM: Fix SVM_CR0_SELECTIVE_MASKAvi Kivity1-1/+1
Instead of selecting TS and MP as the comments say, the macro included TS and PE. Luckily the macro is unused now, but fix in order to save a few hours of debugging from anyone who attempts to use it. Acked-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03KVM: SVM: Support Pause Filter in AMD processorsMark Langsdorf1-1/+2
New AMD processors (Family 0x10 models 8+) support the Pause Filter Feature. This feature creates a new field in the VMCB called Pause Filter Count. If Pause Filter Count is greater than 0 and intercepting PAUSEs is enabled, the processor will increment an internal counter when a PAUSE instruction occurs instead of intercepting. When the internal counter reaches the Pause Filter Count value, a PAUSE intercept will occur. This feature can be used to detect contended spinlocks, especially when the lock holding VCPU is not scheduled. Rescheduling another VCPU prevents the VCPU seeking the lock from wasting its quantum by spinning idly. Experimental results show that most spinlocks are held for less than 1000 PAUSE cycles or more than a few thousand. Default the Pause Filter Counter to 3000 to detect the contended spinlocks. Processor support for this feature is indicated by a CPUID bit. On a 24 core system running 4 guests each with 16 VCPUs, this patch improved overall performance of each guest's 32 job kernbench by approximately 3-5% when combined with a scheduler algorithm thati caused the VCPU to sleep for a brief period. Further performance improvement may be possible with a more sophisticated yield algorithm. Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-06-10KVM: Fix unneeded instruction skipping during task switching.Gleb Natapov1-0/+1
There is no need to skip instruction if the reason for a task switch is a task gate in IDT and access to it is caused by an external even. The problem is currently solved only for VMX since there is no reliable way to skip an instruction in SVM. We should emulate it instead. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2009-03-24KVM: SVM: Move EFER and MSR constants to generic x86 codeAlexander Graf1-4/+0
MSR_EFER_SVME_MASK, MSR_VM_CR and MSR_VM_HSAVE_PA are set in KVM specific headers. Linux does have nice header files to collect EFER bits and MSR IDs, so IMHO we should put them there. While at it, I also changed the naming scheme to match that of the other defines. (introduced in v6) Acked-by: Joerg Roedel <joro@8bytes.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-31KVM: SVM: move svm.h to include/asmEduardo Habkost1-0/+328
svm.h will be used by core code that is independent of KVM, so I am moving it outside the arch/x86/kvm directory. Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>