From: Dave Hansen <dave.hansen@intel.com>
To: Jon Kohler <jon@nutanix.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Tony Luck <tony.luck@intel.com>, Andi Kleen <ak@linux.intel.com>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
linux-kernel@vger.kernel.org
Cc: Borislav Petkov <bp@suse.de>,
Neelima Krishnan <neelima.krishnan@intel.com>,
"kvm @ vger . kernel . org" <kvm@vger.kernel.org>
Subject: Re: [PATCH] x86/tsx: fix KVM guest live migration for tsx=on
Date: Mon, 11 Apr 2022 12:26:52 -0700 [thread overview]
Message-ID: <41a3ca80-d3e2-47d2-8f1c-9235c55de8d1@intel.com> (raw)
In-Reply-To: <20220411180131.5054-1-jon@nutanix.com>
On 4/11/22 11:01, Jon Kohler wrote:
> static enum tsx_ctrl_states x86_get_tsx_auto_mode(void)
> {
> + /*
> + * Hardware will always abort a TSX transaction if both CPUID bits
> + * RTM_ALWAYS_ABORT and TSX_FORCE_ABORT are set. In this case, it is
> + * better not to enumerate CPUID.RTM and CPUID.HLE bits. Clear them
> + * here.
> + */
> + if (boot_cpu_has(X86_FEATURE_RTM_ALWAYS_ABORT) &&
> + boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT)) {
> + tsx_clear_cpuid();
> + setup_clear_cpu_cap(X86_FEATURE_RTM);
> + setup_clear_cpu_cap(X86_FEATURE_HLE);
> + return TSX_CTRL_RTM_ALWAYS_ABORT;
> + }
I don't really like hiding the setup_clear_cpu_cap() like this. Right
now, all of the setup_clear_cpu_cap()'s are in a single function and
they are pretty easy to figure out.
This seems like logic that deserves to be appended down to the last if()
block of code in tsx_init() instead of squirreled away in a "get mode"
function. Does this work?
if (tsx_ctrl_state == TSX_CTRL_DISABLE) {
...
} else if (tsx_ctrl_state == TSX_CTRL_ENABLE) {
...
} else if (tsx_ctrl_state == TSX_CTRL_RTM_ALWAYS_ABORT) {
tsx_clear_cpuid();
setup_clear_cpu_cap(X86_FEATURE_RTM);
setup_clear_cpu_cap(X86_FEATURE_HLE);
}
next prev parent reply other threads:[~2022-04-11 19:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-11 18:01 [PATCH] x86/tsx: fix KVM guest live migration for tsx=on Jon Kohler
2022-04-11 19:26 ` Dave Hansen [this message]
2022-04-11 19:35 ` Jon Kohler
2022-04-11 23:45 ` Dave Hansen
2022-04-12 13:36 ` Jon Kohler
2022-04-12 15:54 ` Dave Hansen
2022-04-12 16:08 ` Jon Kohler
2022-04-12 18:04 ` Pawan Gupta
2022-04-12 18:12 ` Jon Kohler
2022-04-12 20:40 ` Pawan Gupta
2022-04-13 12:43 ` Jon Kohler
2022-04-11 20:07 ` [PATCH v2] " Jon Kohler
2022-04-12 19:55 ` Pawan Gupta
2022-04-12 20:54 ` Pawan Gupta
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