kernel.git/arch/x86/kernel/kvm.c, branch linux-3.17.y

x86, kvm: Clear paravirt_enabled on KVM guests for espfix32's benefit

2015-01-08T18:27:44Z

commit 29fa6825463c97e5157284db80107d1bfac5d77b upstream. paravirt_enabled has the following effects: - Disables the F00F bug workaround warning. There is no F00F bug workaround any more because Linux's standard IDT handling already works around the F00F bug, but the warning still exists. This is only cosmetic, and, in any event, there is no such thing as KVM on a CPU with the F00F bug. - Disables 32-bit APM BIOS detection. On a KVM paravirt system, there should be no APM BIOS anyway. - Disables tboot. I think that the tboot code should check the CPUID hypervisor bit directly if it matters. - paravirt_enabled disables espfix32. espfix32 should *not* be disabled under KVM paravirt. The last point is the purpose of this patch. It fixes a leak of the high 16 bits of the kernel stack address on 32-bit KVM paravirt guests. Fixes CVE-2014-8134. Suggested-by: Konrad Rzeszutek Wilk Signed-off-by: Andy Lutomirski Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-06-13T02:18:49Z

Pull more perf updates from Ingo Molnar: "A second round of perf updates: - wide reaching kprobes sanitization and robustization, with the hope of fixing all 'probe this function crashes the kernel' bugs, by Masami Hiramatsu. - uprobes updates from Oleg Nesterov: tmpfs support, corner case fixes and robustization work. - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo et al: * Add support to accumulate hist periods (Namhyung Kim) * various fixes, refactorings and enhancements" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits) perf: Differentiate exec() and non-exec() comm events perf: Fix perf_event_comm() vs. exec() assumption uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates perf/documentation: Add description for conditional branch filter perf/x86: Add conditional branch filtering support perf/tool: Add conditional branch filter 'cond' to perf record perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND' uprobes: Teach copy_insn() to support tmpfs uprobes: Shift ->readpage check from __copy_insn() to uprobe_register() perf/x86: Use common PMU interrupt disabled code perf/ARM: Use common PMU interrupt disabled code perf: Disable sampled events if no PMU interrupt perf: Fix use after free in perf_remove_from_context() perf tools: Fix 'make help' message error perf record: Fix poll return value propagation perf tools: Move elide bool into perf_hpp_fmt struct perf tools: Remove elide setup for SORT_MODE__MEMORY mode perf tools: Fix "==" into "=" in ui_browser__warning assignment perf tools: Allow overriding sysfs and proc finding with env var perf tools: Consider header files outside perf directory in tags target ...

x86: fix page fault tracing when KVM guest support enabled

2014-05-22T15:47:17Z

I noticed on some of my systems that page fault tracing doesn't work: cd /sys/kernel/debug/tracing echo 1 > events/exceptions/enable cat trace; # nothing shows up I eventually traced it down to CONFIG_KVM_GUEST. At least in a KVM VM, enabling that option breaks page fault tracing, and disabling fixes it. I tried on some old kernels and this does not appear to be a regression: it never worked. There are two page-fault entry functions today. One when tracing is on and another when it is off. The KVM code calls do_page_fault() directly instead of calling the traced version: > dotraplinkage void __kprobes > do_async_page_fault(struct pt_regs *regs, unsigned long > error_code) > { > enum ctx_state prev_state; > > switch (kvm_read_and_reset_pf_reason()) { > default: > do_page_fault(regs, error_code); > break; > case KVM_PV_REASON_PAGE_NOT_PRESENT: I'm also having problems with the page fault tracing on bare metal (same symptom of no trace output). I'm unsure if it's related. Steven had an alternative to this which has zero overhead when tracing is off where this includes the standard noops even when tracing is disabled. I'm unconvinced that the extra complexity of his apporach: http://lkml.kernel.org/r/20140508194508.561ed220@gandalf.local.home is worth it, expecially considering that the KVM code is already making page fault entry slower here. This solution is dirt-simple. Cc: Thomas Gleixner Cc: x86@kernel.org Cc: Peter Zijlstra Cc: Gleb Natapov Cc: kvm@vger.kernel.org Cc: Paolo Bonzini Signed-off-by: Dave Hansen Acked-by: "H. Peter Anvin" Acked-by: Steven Rostedt Signed-off-by: Paolo Bonzini

kprobes, x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation

2014-04-24T08:26:38Z

Use NOKPROBE_SYMBOL macro for protecting functions from kprobes instead of __kprobes annotation under arch/x86. This applies nokprobe_inline annotation for some cases, because NOKPROBE_SYMBOL() will inhibit inlining by referring the symbol address. This just folds a bunch of previous NOKPROBE_SYMBOL() cleanup patches for x86 to one patch. Signed-off-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/20140417081814.26341.51656.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Andrew Morton Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Dave Hansen Cc: Fernando Luis Vázquez Cao Cc: Gleb Natapov Cc: Jason Wang Cc: Jesper Nilsson Cc: Jiri Kosina Cc: Jiri Olsa Cc: Jiri Slaby Cc: Johannes Weiner Cc: Jonathan Lebon Cc: Kees Cook Cc: Matt Fleming Cc: Michel Lespinasse Cc: Paolo Bonzini Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Paul Mackerras Cc: Raghavendra K T Cc: Rusty Russell Cc: Seiji Aguchi Cc: Srivatsa Vaddagiri Cc: Tejun Heo Cc: Vineet Gupta Signed-off-by: Ingo Molnar

kvm: remove redundant registration of BSP's hv_clock area

2014-02-22T14:53:32Z

These days hv_clock allocation is memblock based (i.e. the percpu allocator is not involved), which means that the physical address of each of the per-cpu hv_clock areas is guaranteed to remain unchanged through all its lifetime and we do not need to update its location after CPU bring-up. Signed-off-by: Fernando Luis Vazquez Cao Signed-off-by: Paolo Bonzini

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2014-01-31T16:37:32Z

Pull more KVM updates from Paolo Bonzini: "Second batch of KVM updates. Some minor x86 fixes, two s390 guest features that need some handling in the host, and all the PPC changes. The PPC changes include support for little-endian guests and enablement for new POWER8 features" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (45 commits) x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101 x86, kvm: cache the base of the KVM cpuid leaves kvm: x86: move KVM_CAP_HYPERV_TIME outside #ifdef KVM: PPC: Book3S PR: Cope with doorbell interrupts KVM: PPC: Book3S HV: Add software abort codes for transactional memory KVM: PPC: Book3S HV: Add new state for transactional memory powerpc/Kconfig: Make TM select VSX and VMX KVM: PPC: Book3S HV: Basic little-endian guest support KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells KVM: PPC: Book3S HV: Handle new LPCR bits on POWER8 KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap KVM: PPC: Book3S HV: Implement architecture compatibility modes for POWER8 KVM: PPC: Book3S HV: Add handler for HV facility unavailable KVM: PPC: Book3S HV: Flush the correct number of TLB sets on POWER8 KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers KVM: PPC: Book3S HV: Don't set DABR on POWER8 kvm/ppc: IRQ disabling cleanup ...

x86, asmlinkage, xen, kvm: Make {xen,kvm}_lock_spinning global and visible

2014-01-30T06:17:18Z

These functions are called from inline assembler stubs, thus need to be global and visible. Cc: Konrad Rzeszutek Wilk Cc: Gleb Natapov Cc: Raghavendra K T Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1382458079-24450-7-git-send-email-andi@firstfloor.org Signed-off-by: H. Peter Anvin

x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101

2014-01-29T17:11:55Z

When Hyper-V hypervisor leaves are present, KVM must relocate its own leaves at 0x40000100, because Windows does not look for Hyper-V leaves at indices other than 0x40000000. In this case, the KVM features are at 0x40000101, but the old code would always look at 0x40000001. Fix by using kvm_cpuid_base(). This also requires making the function non-inline, since kvm_cpuid_base() is static. Fixes: 1085ba7f552d84aa8ac0ae903fa8d0cc2ff9f79d Cc: stable@vger.kernel.org Cc: mtosatti@redhat.com Signed-off-by: Paolo Bonzini

x86, kvm: cache the base of the KVM cpuid leaves

2014-01-29T17:11:54Z

It is unnecessary to go through hypervisor_cpuid_base every time a leaf is found (which will be every time a feature is requested after the next patch). Fixes: 1085ba7f552d84aa8ac0ae903fa8d0cc2ff9f79d Cc: stable@vger.kernel.org Cc: mtosatti@redhat.com Signed-off-by: Paolo Bonzini

x86, trace: Register exception handler to trace IDT

2013-11-08T22:15:45Z

This patch registers exception handlers for tracing to a trace IDT. To implemented it in set_intr_gate(), this patch does followings. - Register the exception handlers to the trace IDT by prepending "trace_" to the handler's names. - Also, newly introduce trace_page_fault() to add tracepoints in a subsequent patch. Signed-off-by: Seiji Aguchi Link: http://lkml.kernel.org/r/52716DEC.5050204@hds.com Signed-off-by: H. Peter Anvin