From: Sunil Muthuswamy <sunilmut@microsoft.com>
To: Praveen Kumar <kumarpraveen@linux.microsoft.com>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
"wei.liu@kernel.org" <wei.liu@kernel.org>,
Dexuan Cui <decui@microsoft.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>, "x86@kernel.org" <x86@kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"viremana@linux.microsoft.com" <viremana@linux.microsoft.com>,
"nunodasneves@linux.microsoft.com"
<nunodasneves@linux.microsoft.com>
Subject: RE: [PATCH v4] hyperv: root partition faults writing to VP ASSIST MSR PAGE
Date: Sat, 31 Jul 2021 00:12:45 +0000 [thread overview]
Message-ID: <MW4PR21MB200206D615DEE60044B1F0A6C0ED9@MW4PR21MB2002.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20210730171056.2820-1-kumarpraveen@linux.microsoft.com>
> hv_common_cpu_die(cpu);
>
> - if (hv_vp_assist_page && hv_vp_assist_page[cpu])
> - wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
> + if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
> + union hv_vp_assist_msr_contents msr = {0};
> + if (hv_root_partition) {
> + /*
> + * For Root partition the VP ASSIST page is mapped to
> + * hypervisor provided page, and thus, we unmap the
> + * page here and nullify it, so that in future we have
> + * correct page address mapped in hv_cpu_init.
> + */
> + memunmap(hv_vp_assist_page[cpu]);
> + hv_vp_assist_page[cpu] = NULL;
> + rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
If the vp assist page was previously enabled for root, it will continue to stay enabled
when you 'wrmsr' below. We need to explicitly set the enable bit to 0.
> + }
> + wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
> + }
prev parent reply other threads:[~2021-07-31 0:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 17:10 [PATCH v4] hyperv: root partition faults writing to VP ASSIST MSR PAGE Praveen Kumar
2021-07-31 0:12 ` Sunil Muthuswamy [this message]
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