From: Peter Zijlstra <peterz@infradead.org>
To: Ashok Raj <ashok.raj@intel.com>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Dave Hansen <dave.hansen@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Dan Williams <dan.j.williams@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>
Subject: Re: [PATCH 5/5] x86/feature: Detect the x86 feature Indirect Branch Prediction Barrier
Date: Fri, 12 Jan 2018 11:08:18 +0100 [thread overview]
Message-ID: <20180112100817.GR3040@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1515720739-43819-6-git-send-email-ashok.raj@intel.com>
On Thu, Jan 11, 2018 at 05:32:19PM -0800, Ashok Raj wrote:
> @@ -1711,11 +1715,18 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu)
> __free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);
> kvm_vcpu_uninit(vcpu);
> kmem_cache_free(kvm_vcpu_cache, svm);
> + /*
> + * The VMCB could be recycled, causing a false negative in svm_vcpu_load;
> + * block speculative execution.
> + */
> + if (boot_cpu_has(X86_FEATURE_PRED_CMD))
> + native_wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
> }
> @@ -3837,6 +3839,12 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
> free_vmcs(loaded_vmcs->vmcs);
> loaded_vmcs->vmcs = NULL;
> WARN_ON(loaded_vmcs->shadow_vmcs != NULL);
> + /*
> + * The VMCS could be recycled, causing a false negative in vmx_vcpu_load
> + * block speculative execution.
> + */
> + if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
> + native_wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
> }
Whitespace damage.
Also, why not introduce a helper like:
static inline flush_ibpb(void)
{
if (static_cpu_has(X86_FEATURE_SPEC_CTRL))
native_write_msr(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
}
?
next prev parent reply other threads:[~2018-01-12 10:08 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 1:32 [PATCH 0/5] Add support for IBRS & IBPB KVM support Ashok Raj
2018-01-12 1:32 ` [PATCH 1/5] x86/ibrs: Introduce native_rdmsrl, and native_wrmsrl Ashok Raj
2018-01-12 1:41 ` Andy Lutomirski
2018-01-12 1:52 ` Raj, Ashok
2018-01-12 2:20 ` Andy Lutomirski
2018-01-12 3:01 ` Raj, Ashok
2018-01-12 5:03 ` Dave Hansen
2018-01-12 16:28 ` Josh Poimboeuf
2018-01-12 16:28 ` Woodhouse, David
2018-01-13 6:20 ` Andy Lutomirski
2018-01-13 13:52 ` Van De Ven, Arjan
2018-01-13 15:20 ` Andy Lutomirski
2018-01-13 6:19 ` Andy Lutomirski
2018-01-12 7:54 ` Greg KH
2018-01-12 12:28 ` Borislav Petkov
2018-01-12 1:32 ` [PATCH 2/5] x86/ibrs: Add new helper macros to save/restore MSR_IA32_SPEC_CTRL Ashok Raj
2018-01-12 1:32 ` [PATCH 3/5] x86/ibrs: Add direct access support for MSR_IA32_SPEC_CTRL Ashok Raj
2018-01-12 1:58 ` Dave Hansen
2018-01-12 3:14 ` Raj, Ashok
2018-01-12 9:51 ` Peter Zijlstra
2018-01-12 10:09 ` David Woodhouse
2018-01-15 13:45 ` Peter Zijlstra
2018-01-15 13:59 ` David Woodhouse
2018-01-15 14:45 ` Peter Zijlstra
2018-01-12 1:32 ` [PATCH 4/5] x86/svm: Direct access to MSR_IA32_SPEC_CTRL Ashok Raj
2018-01-12 7:23 ` David Woodhouse
2018-01-12 9:58 ` Peter Zijlstra
2018-01-12 10:13 ` David Woodhouse
2018-01-12 12:38 ` Paolo Bonzini
2018-01-12 15:14 ` Tom Lendacky
2018-01-12 1:32 ` [PATCH 5/5] x86/feature: Detect the x86 feature Indirect Branch Prediction Barrier Ashok Raj
2018-01-12 10:08 ` Peter Zijlstra [this message]
2018-01-12 12:32 ` Borislav Petkov
2018-01-12 12:39 ` Woodhouse, David
2018-01-12 15:21 ` Tom Lendacky
2018-01-12 15:31 ` Tom Lendacky
2018-01-12 15:36 ` Woodhouse, David
2018-01-12 17:06 ` Tom Lendacky
2018-02-01 21:59 [PATCH v6 0/5] KVM: Expose speculation control feature to guests KarimAllah Ahmed
2018-02-01 21:59 ` [PATCH v6 1/5] KVM: x86: Update the reverse_cpuid list to include CPUID_7_EDX KarimAllah Ahmed
2018-02-02 17:37 ` Jim Mattson
2018-02-03 22:50 ` [tip:x86/pti] KVM/x86: " tip-bot for KarimAllah Ahmed
2018-02-01 21:59 ` [PATCH v6 2/5] KVM: x86: Add IBPB support KarimAllah Ahmed
2018-02-02 17:49 ` Konrad Rzeszutek Wilk
2018-02-02 18:02 ` David Woodhouse
2018-02-02 19:56 ` Konrad Rzeszutek Wilk
2018-02-02 20:16 ` David Woodhouse
2018-02-02 20:28 ` Konrad Rzeszutek Wilk
2018-02-02 20:31 ` David Woodhouse
2018-02-02 20:52 ` Konrad Rzeszutek Wilk
2018-02-02 20:52 ` Alan Cox
2018-02-05 19:22 ` Paolo Bonzini
2018-02-05 19:24 ` Paolo Bonzini
2018-02-03 22:50 ` [tip:x86/pti] KVM/x86: " tip-bot for Ashok Raj
2018-02-16 3:44 ` [PATCH v6 2/5] KVM: x86: " Jim Mattson
2018-02-16 4:22 ` Andi Kleen
2018-05-03 1:27 ` Wanpeng Li
2018-05-03 9:19 ` Paolo Bonzini
2018-05-03 12:01 ` Wanpeng Li
2018-05-03 12:46 ` Tian, Kevin
2018-02-01 21:59 ` [PATCH v6 3/5] KVM: VMX: Emulate MSR_IA32_ARCH_CAPABILITIES KarimAllah Ahmed
2018-02-02 10:53 ` Darren Kenny
2018-02-02 17:35 ` Jim Mattson
2018-02-02 17:51 ` Konrad Rzeszutek Wilk
2018-02-03 22:51 ` [tip:x86/pti] KVM/VMX: " tip-bot for KarimAllah Ahmed
2018-02-01 21:59 ` [PATCH v6 4/5] KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL KarimAllah Ahmed
2018-02-02 11:03 ` Darren Kenny
2018-02-02 11:27 ` David Woodhouse
2018-02-02 17:53 ` Konrad Rzeszutek Wilk
2018-02-02 18:05 ` David Woodhouse
2018-02-02 18:19 ` Konrad Rzeszutek Wilk
2018-02-02 17:57 ` Jim Mattson
2018-02-03 22:51 ` [tip:x86/pti] KVM/VMX: " tip-bot for KarimAllah Ahmed
2018-02-01 21:59 ` [PATCH v6 5/5] KVM: SVM: " KarimAllah Ahmed
2018-02-02 11:06 ` Darren Kenny
2018-02-02 18:02 ` Konrad Rzeszutek Wilk
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