From: Jan Beulich <jbeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: "Igor Druzhinin" <igor.druzhinin@citrix.com>,
"Edwin Torok" <edvin.torok@citrix.com>,
"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 3/5] x86/msr: Expose MSR_ARCH_CAPS in the raw and host policies
Date: Mon, 14 Jun 2021 14:57:03 +0200 [thread overview]
Message-ID: <bcb7cacf-f18d-ed74-00b4-854b403bef2e@suse.com> (raw)
In-Reply-To: <20210611163627.4878-4-andrew.cooper3@citrix.com>
On 11.06.2021 18:36, Andrew Cooper wrote:
> @@ -60,6 +65,11 @@ static void __init calculate_host_policy(void)
> /* 0x000000ce MSR_INTEL_PLATFORM_INFO */
> /* probe_cpuid_faulting() sanity checks presence of MISC_FEATURES_ENABLES */
> mp->platform_info.cpuid_faulting = cpu_has_cpuid_faulting;
> +
> + mp->arch_caps.raw &=
> + (ARCH_CAPS_RDCL_NO | ARCH_CAPS_IBRS_ALL | ARCH_CAPS_RSBA |
> + ARCH_CAPS_SKIP_L1DFL | ARCH_CAPS_SSB_NO | ARCH_CAPS_MDS_NO |
> + ARCH_CAPS_IF_PSCHANGE_MC_NO | ARCH_CAPS_TSX_CTRL | ARCH_CAPS_TAA_NO);
> }
Isn't this a little too simple? For CPUID we consider the host policy
to be what Xen is using. Taking ARCH_CAPS_SKIP_L1DFL as an example,
we're not using it unconditionally (depending on opt_md_clear_hvm and
opt_l1d_flush), i.e. there's command line control over its use just
like there is over the CPUID bits. Or take ARCH_CAPS_RDCL_NO, which
we set unilaterally for AMD/Hygon.
I don't mind it remaining this simple for the moment, but then at
least the commit message should state that this is currently over-
simplifying things. If you agree, then with suitable wording added:
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Jan
next prev parent reply other threads:[~2021-06-14 12:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-11 16:36 [PATCH 0/5] x86/tsx: Consistency and settings test Andrew Cooper
2021-06-11 16:36 ` [PATCH 1/5] x86/platform: Improve MSR permission handling for XENPF_resource_op Andrew Cooper
2021-06-14 12:45 ` Jan Beulich
2021-06-11 16:36 ` [PATCH 2/5] x86/platform: Permit reading the TSX control MSRs via XENPF_resource_op Andrew Cooper
2021-06-14 12:46 ` Jan Beulich
2021-06-11 16:36 ` [PATCH 3/5] x86/msr: Expose MSR_ARCH_CAPS in the raw and host policies Andrew Cooper
2021-06-14 12:57 ` Jan Beulich [this message]
2021-06-14 14:10 ` Andrew Cooper
2021-06-14 14:54 ` Jan Beulich
2021-06-11 16:36 ` [PATCH 4/5] libs/guest: Move struct xc_cpu_policy into xg_private.h Andrew Cooper
2021-06-14 13:00 ` Jan Beulich
2021-06-14 13:49 ` Ian Jackson
2021-06-14 13:56 ` Jan Beulich
2021-06-11 16:36 ` [PATCH 5/5] tests: Introduce a TSX test Andrew Cooper
2021-06-14 10:47 ` [PATCH v1.1 " Andrew Cooper
2021-06-14 13:31 ` Jan Beulich
2021-06-14 14:50 ` Andrew Cooper
2021-06-14 14:59 ` Jan Beulich
2021-06-14 15:55 ` Edwin Torok
2021-06-14 16:32 ` Andrew Cooper
2021-06-14 16:13 ` [PATCH v2 " Andrew Cooper
2021-06-14 17:21 ` Andrew Cooper
2021-06-15 13:49 ` Jan Beulich
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