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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-16 14:58:12 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-16 14:58:12 -0800 |
commit | 37507717de51a8332a34ee07fd88700be88df5bf (patch) | |
tree | d6eb5d00a798a4b1ce40c8c4c8ca74b0d22fe1df /arch/x86/kvm/vmx.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/vmx.c')
-rw-r--r-- | arch/x86/kvm/vmx.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3f73bfad0349..14c1a18d206a 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2871,7 +2871,7 @@ static int hardware_enable(void) u64 phys_addr = __pa(per_cpu(vmxarea, cpu)); u64 old, test_bits; - if (read_cr4() & X86_CR4_VMXE) + if (cr4_read_shadow() & X86_CR4_VMXE) return -EBUSY; INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); @@ -2898,7 +2898,7 @@ static int hardware_enable(void) /* enable and lock */ wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits); } - write_cr4(read_cr4() | X86_CR4_VMXE); /* FIXME: not cpu hotplug safe */ + cr4_set_bits(X86_CR4_VMXE); if (vmm_exclusive) { kvm_cpu_vmxon(phys_addr); @@ -2935,7 +2935,7 @@ static void hardware_disable(void) vmclear_local_loaded_vmcss(); kvm_cpu_vmxoff(); } - write_cr4(read_cr4() & ~X86_CR4_VMXE); + cr4_clear_bits(X86_CR4_VMXE); } static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt, @@ -4450,7 +4450,7 @@ static void vmx_set_constant_host_state(struct vcpu_vmx *vmx) vmcs_writel(HOST_CR3, read_cr3()); /* 22.2.3 FIXME: shadow tables */ /* Save the most likely value for this task's CR4 in the VMCS. */ - cr4 = read_cr4(); + cr4 = cr4_read_shadow(); vmcs_writel(HOST_CR4, cr4); /* 22.2.3, 22.2.5 */ vmx->host_state.vmcs_host_cr4 = cr4; @@ -8146,7 +8146,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) if (test_bit(VCPU_REGS_RIP, (unsigned long *)&vcpu->arch.regs_dirty)) vmcs_writel(GUEST_RIP, vcpu->arch.regs[VCPU_REGS_RIP]); - cr4 = read_cr4(); + cr4 = cr4_read_shadow(); if (unlikely(cr4 != vmx->host_state.vmcs_host_cr4)) { vmcs_writel(HOST_CR4, cr4); vmx->host_state.vmcs_host_cr4 = cr4; |