From: Wei Liu <wei.liu2@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Juergen Gross" <jgross@suse.com>,
"Wei Liu" <wei.liu2@citrix.com>,
"Zhenzhong Duan" <zhenzhong.duan@oracle.com>,
Xen-devel <xen-devel@lists.xen.org>,
"Jan Beulich" <JBeulich@suse.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 07/10] x86/spec_ctrl: Explicitly set Xen's default MSR_SPEC_CTRL value
Date: Mon, 14 May 2018 16:39:21 +0100 [thread overview]
Message-ID: <20180514153921.r2ro7ibv3bekvyfa@citrix.com> (raw)
In-Reply-To: <1526035094-14343-8-git-send-email-andrew.cooper3@citrix.com>
On Fri, May 11, 2018 at 11:38:11AM +0100, Andrew Cooper wrote:
> @@ -417,6 +419,32 @@ void __init init_speculation_mitigations(void)
> setup_clear_cpu_cap(X86_FEATURE_NO_XPTI);
>
> print_details(thunk, caps);
> +
> + /*
> + * If MSR_SPEC_CTRL is available, apply Xen's default setting and discard
> + * any firmware settings. For performance reasons on native hardware, we
> + * delay applying non-zero settings until after dom0 has been constructed.
> + */
> + if ( boot_cpu_has(X86_FEATURE_IBRSB) )
> + {
> + bsp_delay_spec_ctrl = !cpu_has_hypervisor && default_xen_spec_ctrl;
> +
Why is cpu_has_hypervisor needed here? This should help nested case as
well. And it wouldn't make the setup less secure, right?
Wei.
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next prev parent reply other threads:[~2018-05-14 15:39 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-11 10:38 [PATCH for-4.11 00/10] x86: Improvements and fixes to Spectre handling Andrew Cooper
2018-05-11 10:38 ` [PATCH 01/10] x86/spec_ctrl: Read MSR_ARCH_CAPABILITIES only once Andrew Cooper
2018-05-11 14:32 ` Konrad Rzeszutek Wilk
2018-05-14 9:23 ` Wei Liu
2018-05-11 10:38 ` [PATCH 02/10] x86/spec_ctrl: Express Xen's choice of MSR_SPEC_CTRL value as a variable Andrew Cooper
2018-05-14 10:15 ` Wei Liu
2018-05-11 10:38 ` [PATCH 03/10] x86/spec_ctrl: Merge bti_ist_info and use_shadow_spec_ctrl into spec_ctrl_flags Andrew Cooper
2018-05-14 15:13 ` Wei Liu
2018-05-11 10:38 ` [PATCH 04/10] x86/spec_ctrl: Fold the XEN_IBRS_{SET, CLEAR} ALTERNATIVES together Andrew Cooper
2018-05-14 15:20 ` Wei Liu
2018-05-11 10:38 ` [PATCH 05/10] x86/spec_ctrl: Rename bits of infrastructure to avoid NATIVE and VMEXIT Andrew Cooper
2018-05-14 15:21 ` Wei Liu
2018-05-11 10:38 ` [PATCH 06/10] x86/spec_ctrl: Split X86_FEATURE_SC_MSR into PV and HVM variants Andrew Cooper
2018-05-14 15:22 ` Wei Liu
2018-05-14 15:27 ` Jan Beulich
2018-05-15 19:52 ` Andrew Cooper
2018-05-16 6:38 ` Jan Beulich
2018-05-16 10:28 ` Andrew Cooper
2018-05-16 10:49 ` Jan Beulich
2018-05-16 10:56 ` Andrew Cooper
2018-05-11 10:38 ` [PATCH 07/10] x86/spec_ctrl: Explicitly set Xen's default MSR_SPEC_CTRL value Andrew Cooper
2018-05-14 15:39 ` Wei Liu [this message]
2018-05-14 15:52 ` Jan Beulich
2018-05-16 11:08 ` Andrew Cooper
2018-05-16 11:12 ` Wei Liu
2018-05-11 10:38 ` [PATCH 08/10] x86/cpuid: Improvements to guest policies for speculative sidechannel features Andrew Cooper
2018-05-11 10:38 ` [PATCH 09/10] x86/spec_ctrl: Introduce a new `spec-ctrl=` command line argument to replace `bti=` Andrew Cooper
2018-05-11 10:38 ` [PATCH 10/10] x86/spec_ctrl: Elide MSR_SPEC_CTRL handling in idle context when possible Andrew Cooper
2018-05-14 15:48 ` Wei Liu
2018-05-16 11:27 ` Andrew Cooper
2018-05-16 11:28 ` Wei Liu
2018-05-14 9:23 ` [PATCH for-4.11 00/10] x86: Improvements and fixes to Spectre handling Wei Liu
2018-05-14 15:31 ` Jan Beulich
2018-05-15 18:25 ` Juergen Gross
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