From: Jim Mattson <jmattson@google.com>
To: KarimAllah Ahmed <karahmed@amazon.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Andi Kleen" <ak@linux.intel.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Arjan van de Ven" <arjan@linux.intel.com>,
"Ashok Raj" <ashok.raj@intel.com>,
"Asit Mallick" <asit.k.mallick@intel.com>,
"Borislav Petkov" <bp@suse.de>,
"Dan Williams" <dan.j.williams@intel.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"David Woodhouse" <dwmw@amazon.co.uk>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"H . Peter Anvin" <hpa@zytor.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Janakarajan Natarajan" <Janakarajan.Natarajan@amd.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Jun Nakajima" <jun.nakajima@intel.com>,
"Laura Abbott" <labbott@redhat.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Tim Chen" <tim.c.chen@linux.intel.com>,
"Tom Lendacky" <thomas.lendacky@amd.com>,
"kvm list" <kvm@vger.kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
"Arjan Van De Ven" <arjan.van.de.ven@intel.com>
Subject: Re: [RFC 02/10] x86/kvm: Add IBPB support
Date: Mon, 22 Jan 2018 11:31:16 -0800 [thread overview]
Message-ID: <CALMp9eTrzJ6gdBF9XvU5bg1=rN1U4Y-C30Z+c3pcf0iNpfzqdA@mail.gmail.com> (raw)
In-Reply-To: <CALMp9eSdKyaAgxS1CLXgQ7GzFns7Agvr5kx67v87O9JT=1ypmA@mail.gmail.com>
Oh, but to do that properly, you need one of the per-vCPU bitmap
implementations that Paolo and I have independently posted.
On Mon, Jan 22, 2018 at 10:56 AM, Jim Mattson <jmattson@google.com> wrote:
> On Sat, Jan 20, 2018 at 11:22 AM, KarimAllah Ahmed <karahmed@amazon.de> wrote:
>> From: Ashok Raj <ashok.raj@intel.com>
>>
>> Add MSR passthrough for MSR_IA32_PRED_CMD and place branch predictor
>> barriers on switching between VMs to avoid inter VM specte-v2 attacks.
>>
>> [peterz: rebase and changelog rewrite]
>> [dwmw2: fixes]
>> [karahmed: - vmx: expose PRED_CMD whenever it is available
>> - svm: only pass through IBPB if it is available]
>>
>> Cc: Asit Mallick <asit.k.mallick@intel.com>
>> Cc: Dave Hansen <dave.hansen@intel.com>
>> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
>> Cc: Tim Chen <tim.c.chen@linux.intel.com>
>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>> Cc: Andrea Arcangeli <aarcange@redhat.com>
>> Cc: Andi Kleen <ak@linux.intel.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Dan Williams <dan.j.williams@intel.com>
>> Cc: Jun Nakajima <jun.nakajima@intel.com>
>> Cc: Andy Lutomirski <luto@kernel.org>
>> Cc: Greg KH <gregkh@linuxfoundation.org>
>> Cc: David Woodhouse <dwmw@amazon.co.uk>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>> Link: http://lkml.kernel.org/r/1515720739-43819-6-git-send-email-ashok.raj@intel.com
>>
>> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
>> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
>> ---
>> arch/x86/kvm/svm.c | 14 ++++++++++++++
>> arch/x86/kvm/vmx.c | 4 ++++
>> 2 files changed, 18 insertions(+)
>>
>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>> index 2744b973..cfdb9ab 100644
>> --- a/arch/x86/kvm/svm.c
>> +++ b/arch/x86/kvm/svm.c
>> @@ -529,6 +529,7 @@ struct svm_cpu_data {
>> struct kvm_ldttss_desc *tss_desc;
>>
>> struct page *save_area;
>> + struct vmcb *current_vmcb;
>> };
>>
>> static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data);
>> @@ -918,6 +919,9 @@ static void svm_vcpu_init_msrpm(u32 *msrpm)
>>
>> set_msr_interception(msrpm, direct_access_msrs[i].index, 1, 1);
>> }
>> +
>> + if (boot_cpu_has(X86_FEATURE_AMD_PRED_CMD))
>> + set_msr_interception(msrpm, MSR_IA32_PRED_CMD, 1, 1);
>> }
>>
>> static void add_msr_offset(u32 offset)
>> @@ -1706,11 +1710,17 @@ 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 page can be recycled, causing a false negative in
>> + * svm_vcpu_load(). So do a full IBPB now.
>> + */
>> + indirect_branch_prediction_barrier();
>> }
>>
>> static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>> {
>> struct vcpu_svm *svm = to_svm(vcpu);
>> + struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
>> int i;
>>
>> if (unlikely(cpu != vcpu->cpu)) {
>> @@ -1739,6 +1749,10 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>> if (static_cpu_has(X86_FEATURE_RDTSCP))
>> wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
>>
>> + if (sd->current_vmcb != svm->vmcb) {
>> + sd->current_vmcb = svm->vmcb;
>> + indirect_branch_prediction_barrier();
>> + }
>> avic_vcpu_load(vcpu, cpu);
>> }
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index d1e25db..3b64de2 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -2279,6 +2279,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>> if (per_cpu(current_vmcs, cpu) != vmx->loaded_vmcs->vmcs) {
>> per_cpu(current_vmcs, cpu) = vmx->loaded_vmcs->vmcs;
>> vmcs_load(vmx->loaded_vmcs->vmcs);
>> + indirect_branch_prediction_barrier();
>> }
>>
>> if (!already_loaded) {
>> @@ -6791,6 +6792,9 @@ static __init int hardware_setup(void)
>> kvm_tsc_scaling_ratio_frac_bits = 48;
>> }
>>
>> + if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
>
> I think the condition here should be:
>
> if (guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
>
> __do_cpuid_ent should pass through X86_FEATURE_SPEC_CTRL from the
> host, but userspace should be allowed to clear it.
> (Userspace should not be allowed to set it if the host doesn't support it.)
>
>> + vmx_disable_intercept_for_msr(MSR_IA32_PRED_CMD, false);
>> +
>> vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
>> vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
>> vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
>> --
>> 2.7.4
>>
next prev parent reply other threads:[~2018-01-22 19:31 UTC|newest]
Thread overview: 137+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-20 19:22 [RFC 00/10] Speculation Control feature support KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 01/10] x86/speculation: Add basic support for IBPB KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 02/10] x86/kvm: Add IBPB support KarimAllah Ahmed
2018-01-20 20:18 ` Woodhouse, David
2018-01-22 18:56 ` Jim Mattson
2018-01-22 19:31 ` Jim Mattson [this message]
2018-01-20 19:22 ` [RFC 03/10] x86/speculation: Use Indirect Branch Prediction Barrier in context switch KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 04/10] x86/mm: Only flush indirect branches when switching into non dumpable process KarimAllah Ahmed
2018-01-20 21:06 ` Woodhouse, David
2018-01-22 18:29 ` Tim Chen
2018-01-21 11:22 ` Peter Zijlstra
2018-01-21 12:04 ` David Woodhouse
2018-01-21 14:07 ` H.J. Lu
2018-01-22 10:19 ` Peter Zijlstra
2018-01-22 10:23 ` David Woodhouse
2018-01-21 16:21 ` Ingo Molnar
2018-01-21 16:25 ` Arjan van de Ven
2018-01-21 22:20 ` Woodhouse, David
2018-01-29 6:35 ` Jon Masters
2018-01-29 14:07 ` Peter Zijlstra
2018-01-20 19:22 ` [RFC 05/10] x86/speculation: Add basic IBRS support infrastructure KarimAllah Ahmed
2018-01-21 14:31 ` Thomas Gleixner
2018-01-21 14:56 ` Borislav Petkov
2018-01-22 9:51 ` Peter Zijlstra
2018-01-22 12:06 ` Borislav Petkov
2018-01-22 13:30 ` Greg Kroah-Hartman
2018-01-22 13:37 ` Woodhouse, David
2018-01-21 15:25 ` David Woodhouse
2018-01-23 20:58 ` David Woodhouse
2018-01-23 22:43 ` Johannes Erdfelt
2018-01-24 8:47 ` Peter Zijlstra
2018-01-24 9:02 ` David Woodhouse
2018-01-24 9:10 ` Greg Kroah-Hartman
2018-01-24 15:09 ` Arjan van de Ven
2018-01-24 15:18 ` David Woodhouse
2018-01-24 9:34 ` Peter Zijlstra
2018-01-24 10:49 ` Henrique de Moraes Holschuh
2018-01-24 12:30 ` David Woodhouse
2018-01-24 12:14 ` David Woodhouse
2018-01-24 12:29 ` Peter Zijlstra
2018-01-24 12:58 ` David Woodhouse
2018-01-29 20:14 ` [RFC,05/10] " Eduardo Habkost
2018-01-29 20:17 ` David Woodhouse
2018-01-29 20:42 ` Eduardo Habkost
2018-01-29 20:44 ` Arjan van de Ven
2018-01-29 21:02 ` David Woodhouse
2018-01-29 21:37 ` Jim Mattson
2018-01-29 21:50 ` Eduardo Habkost
2018-01-29 22:12 ` Jim Mattson
2018-01-30 1:22 ` Eduardo Habkost
2018-01-29 22:25 ` Andi Kleen
2018-01-30 1:37 ` Eduardo Habkost
2018-01-29 21:37 ` Andi Kleen
2018-01-29 21:44 ` Eduardo Habkost
2018-01-29 22:10 ` Konrad Rzeszutek Wilk
2018-01-30 1:12 ` Eduardo Habkost
2018-01-30 0:23 ` Linus Torvalds
2018-01-30 1:03 ` Jim Mattson
2018-01-30 3:13 ` Andi Kleen
2018-01-31 15:03 ` Paolo Bonzini
2018-01-31 15:07 ` Dr. David Alan Gilbert
2018-01-30 1:32 ` Arjan van de Ven
2018-01-30 3:32 ` Linus Torvalds
2018-01-30 12:04 ` Eduardo Habkost
2018-01-30 13:54 ` Arjan van de Ven
2018-01-30 8:22 ` David Woodhouse
2018-01-30 11:35 ` David Woodhouse
2018-01-30 11:56 ` Dr. David Alan Gilbert
2018-01-30 12:11 ` Christian Borntraeger
2018-01-30 14:46 ` Christophe de Dinechin
2018-01-30 14:52 ` Christian Borntraeger
2018-01-30 14:56 ` Christophe de Dinechin
2018-01-30 15:33 ` Christian Borntraeger
2018-01-30 20:46 ` Alan Cox
2018-01-31 10:05 ` Christophe de Dinechin
2018-01-31 10:15 ` Thomas Gleixner
2018-01-31 11:04 ` Dr. David Alan Gilbert
2018-01-31 11:52 ` Borislav Petkov
2018-01-31 12:30 ` Dr. David Alan Gilbert
2018-01-31 13:18 ` Borislav Petkov
2018-01-31 14:04 ` Dr. David Alan Gilbert
2018-01-31 14:44 ` Eduardo Habkost
2018-01-31 16:28 ` Borislav Petkov
2018-01-31 11:07 ` Christophe de Dinechin
2018-01-31 15:00 ` Eduardo Habkost
2018-01-31 15:11 ` Arjan van de Ven
2018-01-31 10:03 ` [RFC 05/10] " Christophe de Dinechin
2018-01-20 19:22 ` [RFC 06/10] x86/speculation: Add inlines to control Indirect Branch Speculation KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 07/10] x86: Simplify spectre_v2 command line parsing KarimAllah Ahmed
2018-01-20 19:22 ` [RFC 08/10] x86/idle: Control Indirect Branch Speculation in idle KarimAllah Ahmed
2018-01-20 19:23 ` [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation KarimAllah Ahmed
2018-01-21 19:14 ` Andy Lutomirski
2018-01-23 16:12 ` Tom Lendacky
2018-01-23 16:20 ` Woodhouse, David
2018-01-23 22:37 ` Tom Lendacky
2018-01-23 22:49 ` Andi Kleen
2018-01-23 23:14 ` Woodhouse, David
2018-01-23 23:22 ` Andi Kleen
2018-01-24 0:47 ` Tim Chen
2018-01-24 1:00 ` Andy Lutomirski
2018-01-24 1:22 ` David Woodhouse
2018-01-24 1:59 ` Van De Ven, Arjan
2018-01-24 3:25 ` Andy Lutomirski
2018-01-21 19:34 ` Linus Torvalds
2018-01-21 20:28 ` David Woodhouse
2018-01-21 21:35 ` Linus Torvalds
2018-01-21 22:00 ` David Woodhouse
2018-01-21 22:27 ` Linus Torvalds
2018-01-22 16:27 ` David Woodhouse
2018-01-23 7:29 ` Ingo Molnar
2018-01-23 7:53 ` Ingo Molnar
2018-01-23 9:27 ` Ingo Molnar
2018-01-23 9:37 ` David Woodhouse
2018-01-23 15:01 ` Dave Hansen
2018-01-23 9:30 ` David Woodhouse
2018-01-23 10:15 ` Ingo Molnar
2018-01-23 10:27 ` David Woodhouse
2018-01-23 10:44 ` Ingo Molnar
2018-01-23 10:57 ` David Woodhouse
2018-01-23 10:23 ` Ingo Molnar
2018-01-23 10:35 ` David Woodhouse
2018-02-04 18:43 ` Thomas Gleixner
2018-02-04 20:22 ` David Woodhouse
2018-02-06 9:14 ` David Woodhouse
2018-01-25 16:19 ` Mason
2018-01-25 17:16 ` Greg Kroah-Hartman
2018-01-29 11:59 ` Mason
2018-01-24 0:05 ` Andi Kleen
2018-01-23 20:16 ` Pavel Machek
2018-01-20 19:23 ` [RFC 10/10] x86/enter: Use IBRS on syscall and interrupts KarimAllah Ahmed
2018-01-21 13:50 ` Konrad Rzeszutek Wilk
2018-01-21 14:40 ` KarimAllah Ahmed
2018-01-21 17:22 ` Dave Hansen
2018-01-21 14:02 ` [RFC 00/10] Speculation Control feature support Konrad Rzeszutek Wilk
2018-01-22 21:27 ` David Woodhouse
2018-01-20 20:28 [RFC 02/10] x86/kvm: Add IBPB support Liran Alon
2018-01-20 20:36 ` Woodhouse, David
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