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Date: Tue, 17 Oct 2017 15:35:55 +0200
From: Borislav Petkov <bp@alien8.de>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        Tom Lendacky <thomas.lendacky@amd.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Subject: Re: [Part1 PATCH v6 16/17] X86/KVM: Decrypt shared per-cpu variables
 when SEV is active
Message-ID: <20171017133555.de4omyuoveaijkk6@pd.tnic>
References: <20171016153423.2980-1-brijesh.singh@amd.com>
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On Tue, Oct 17, 2017 at 06:54:52AM -0500, Brijesh Singh wrote:
> Will do. Do you want me to send v7 with that addressed. Because this
> require changes in 3 patches (PATCH 14, 16, 17)

Just send me those three first as a reply to the thread so that I can
test the whole queue everywhere. Or even better, point me to the v7 git
branch once you have it ready.

> The second call is for UP cases. The kvm_smp_prepapre_boot_cpu() is
> called only when CONFIG_SMP is enabled. Am I missing something ?

Yes, you are.

kvm_guest_init() gets called unconditionally from setup_arch(). But then
you said kvm_guest_init() is called before setup_per_cpu_areas() so why
do you need that call there at all? percpu areas are not ready yet, what
makes them ready in the UP case?

IOW, this sev_map_percpu_data() needs to happen only once, during boot.
So call it only once by finding the right spot and not by adding a
second call for the UP case.

AFAICT, it looks the easiest if you put it in kvm_guest_cpu_init() and
do something like:

	if (smp_processor_id() == boot_cpu_data.cpu_index)
		sev_map_percpu_data();

...

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.