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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-16 14:58:12 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-16 14:58:12 -0800 |
| commit | 37507717de51a8332a34ee07fd88700be88df5bf (patch) | |
| tree | d6eb5d00a798a4b1ce40c8c4c8ca74b0d22fe1df /arch/x86/kvm/svm.c | |
| parent | a68fb48380bb993306dd62a58cbd946b4348222a (diff) | |
| parent | a66734297f78707ce39d756b656bfae861d53f62 (diff) | |
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 perf updates from Ingo Molnar:
"This series tightens up RDPMC permissions: currently even highly
sandboxed x86 execution environments (such as seccomp) have permission
to execute RDPMC, which may leak various perf events / PMU state such
as timing information and other CPU execution details.
This 'all is allowed' RDPMC mode is still preserved as the
(non-default) /sys/devices/cpu/rdpmc=2 setting. The new default is
that RDPMC access is only allowed if a perf event is mmap-ed (which is
needed to correctly interpret RDPMC counter values in any case).
As a side effect of these changes CR4 handling is cleaned up in the
x86 code and a shadow copy of the CR4 value is added.
The extra CR4 manipulation adds ~ <50ns to the context switch cost
between rdpmc-capable and rdpmc-non-capable mms"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks
perf/x86: Only allow rdpmc if a perf_event is mapped
perf: Pass the event to arch_perf_update_userpage()
perf: Add pmu callbacks to track event mapping and unmapping
x86: Add a comment clarifying LDT context switching
x86: Store a per-cpu shadow copy of CR4
x86: Clean up cr4 manipulation
Diffstat (limited to 'arch/x86/kvm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index a17d848c6d4..d319e0c2475 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1583,7 +1583,7 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) static int svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) { - unsigned long host_cr4_mce = read_cr4() & X86_CR4_MCE; + unsigned long host_cr4_mce = cr4_read_shadow() & X86_CR4_MCE; unsigned long old_cr4 = to_svm(vcpu)->vmcb->save.cr4; if (cr4 & X86_CR4_VMXE) |