summaryrefslogtreecommitdiffstats
path: root/include
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-11-12 10:53:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-12 10:53:24 -0800
commiteb094f06963bb0fd8134c6a9b805d4ad0002a7d4 (patch)
tree0883296aa979d616ea8df6cfb42d333338c6d583 /include
parent100d46bd72ec689a5582c2f5f4deadc5bcb92d60 (diff)
parent012206a822a8b6ac09125bfaa210a95b9eb8f1c1 (diff)
downloadlinux-eb094f06963bb0fd8134c6a9b805d4ad0002a7d4.tar.bz2
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 TSX Async Abort and iTLB Multihit mitigations from Thomas Gleixner: "The performance deterioration departement is not proud at all of presenting the seventh installment of speculation mitigations and hardware misfeature workarounds: 1) TSX Async Abort (TAA) - 'The Annoying Affair' TAA is a hardware vulnerability that allows unprivileged speculative access to data which is available in various CPU internal buffers by using asynchronous aborts within an Intel TSX transactional region. The mitigation depends on a microcode update providing a new MSR which allows to disable TSX in the CPU. CPUs which have no microcode update can be mitigated by disabling TSX in the BIOS if the BIOS provides a tunable. Newer CPUs will have a bit set which indicates that the CPU is not vulnerable, but the MSR to disable TSX will be available nevertheless as it is an architected MSR. That means the kernel provides the ability to disable TSX on the kernel command line, which is useful as TSX is a truly useful mechanism to accelerate side channel attacks of all sorts. 2) iITLB Multihit (NX) - 'No eXcuses' iTLB Multihit is an erratum where some Intel processors may incur a machine check error, possibly resulting in an unrecoverable CPU lockup, when an instruction fetch hits multiple entries in the instruction TLB. This can occur when the page size is changed along with either the physical address or cache type. A malicious guest running on a virtualized system can exploit this erratum to perform a denial of service attack. The workaround is that KVM marks huge pages in the extended page tables as not executable (NX). If the guest attempts to execute in such a page, the page is broken down into 4k pages which are marked executable. The workaround comes with a mechanism to recover these shattered huge pages over time. Both issues come with full documentation in the hardware vulnerabilities section of the Linux kernel user's and administrator's guide. Thanks to all patch authors and reviewers who had the extraordinary priviledge to be exposed to this nuisance. Special thanks to Borislav Petkov for polishing the final TAA patch set and to Paolo Bonzini for shepherding the KVM iTLB workarounds and providing also the backports to stable kernels for those!" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/speculation/taa: Fix printing of TAA_MSG_SMT on IBRS_ALL CPUs Documentation: Add ITLB_MULTIHIT documentation kvm: x86: mmu: Recovery of shattered NX large pages kvm: Add helper function for creating VM worker threads kvm: mmu: ITLB_MULTIHIT mitigation cpu/speculation: Uninline and export CPU mitigations helpers x86/cpu: Add Tremont to the cpu vulnerability whitelist x86/bugs: Add ITLB_MULTIHIT bug infrastructure x86/tsx: Add config options to set tsx=on|off|auto x86/speculation/taa: Add documentation for TSX Async Abort x86/tsx: Add "auto" option to the tsx= cmdline parameter kvm/x86: Export MDS_NO=0 to guests when TSX is enabled x86/speculation/taa: Add sysfs reporting for TSX Async Abort x86/speculation/taa: Add mitigation for TSX Async Abort x86/cpu: Add a "tsx=" cmdline option with TSX disabled by default x86/cpu: Add a helper function x86_read_arch_cap_msr() x86/msr: Add the IA32_TSX_CTRL MSR
Diffstat (limited to 'include')
-rw-r--r--include/linux/cpu.h30
-rw-r--r--include/linux/kvm_host.h6
2 files changed, 13 insertions, 23 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index d0633ebdaa9c..bc6c879bd110 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -59,6 +59,11 @@ extern ssize_t cpu_show_l1tf(struct device *dev,
struct device_attribute *attr, char *buf);
extern ssize_t cpu_show_mds(struct device *dev,
struct device_attribute *attr, char *buf);
+extern ssize_t cpu_show_tsx_async_abort(struct device *dev,
+ struct device_attribute *attr,
+ char *buf);
+extern ssize_t cpu_show_itlb_multihit(struct device *dev,
+ struct device_attribute *attr, char *buf);
extern __printf(4, 5)
struct device *cpu_device_create(struct device *parent, void *drvdata,
@@ -213,28 +218,7 @@ static inline int cpuhp_smt_enable(void) { return 0; }
static inline int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { return 0; }
#endif
-/*
- * These are used for a global "mitigations=" cmdline option for toggling
- * optional CPU mitigations.
- */
-enum cpu_mitigations {
- CPU_MITIGATIONS_OFF,
- CPU_MITIGATIONS_AUTO,
- CPU_MITIGATIONS_AUTO_NOSMT,
-};
-
-extern enum cpu_mitigations cpu_mitigations;
-
-/* mitigations=off */
-static inline bool cpu_mitigations_off(void)
-{
- return cpu_mitigations == CPU_MITIGATIONS_OFF;
-}
-
-/* mitigations=auto,nosmt */
-static inline bool cpu_mitigations_auto_nosmt(void)
-{
- return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
-}
+extern bool cpu_mitigations_off(void);
+extern bool cpu_mitigations_auto_nosmt(void);
#endif /* _LINUX_CPU_H_ */
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 719fc3e15ea4..52ed5f66e8f9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1382,4 +1382,10 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
}
#endif /* CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE */
+typedef int (*kvm_vm_thread_fn_t)(struct kvm *kvm, uintptr_t data);
+
+int kvm_vm_create_worker_thread(struct kvm *kvm, kvm_vm_thread_fn_t thread_fn,
+ uintptr_t data, const char *name,
+ struct task_struct **thread_ptr);
+
#endif