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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Borislav Petkov <bp@suse.de>
Cc: "Brijesh Singh" <brijesh.singh@amd.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, "Tom Lendacky" <thomas.lendacky@amd.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH v5 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active
Date: Thu, 6 Sep 2018 11:45:03 -0700	[thread overview]
Message-ID: <20180906184503.GA4570@linux.intel.com> (raw)
In-Reply-To: <20180906183334.GF11144@zn.tnic>

On Thu, Sep 06, 2018 at 08:33:34PM +0200, Borislav Petkov wrote:
> On Thu, Sep 06, 2018 at 08:54:52AM -0700, Sean Christopherson wrote:
> > My thought was that we could simply define a second array for the SEV
> > case to statically allocate for NR_CPUS since __decrypted has a big
> > chunk of memory that would be ununsed anyways[1]. And since the second
> > array is only used for SEV it can be freed if !SEV.
> 
> Lemme see if I get it straight:
> 
> __decrypted:
> 
>  4K
> 
> __decrypted_XXX:
> 
>  ((num_possible_cpus() * 32) / 4K) pages
> 
> __decrypted_end:
> 
> Am I close?

Yep, though because the 4k chunk in __decrypted is @hv_clock_boot 
that's used for cpus 0-127, __decrypted_XXX would effectively be:

   (((num_possible_cpus() * 32) / 4k) - 1) pages

  parent reply	other threads:[~2018-09-06 18:45 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-06 11:42 [PATCH v5 0/5] x86: Fix SEV guest regression Brijesh Singh
2018-09-06 11:42 ` [PATCH v5 1/5] x86/mm: Restructure sme_encrypt_kernel() Brijesh Singh
2018-09-06 11:42 ` [PATCH v5 2/5] x86/mm: fix sme_populate_pgd() to update page flags Brijesh Singh
2018-09-06 11:43 ` [PATCH v5 3/5] x86/mm: add .data..decrypted section to hold shared variables Brijesh Singh
2018-09-06 11:43 ` [PATCH v5 4/5] x86/kvm: use __decrypted attribute in " Brijesh Singh
2018-09-06 11:43 ` [PATCH v5 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active Brijesh Singh
2018-09-06 12:24   ` Borislav Petkov
2018-09-06 13:50     ` Sean Christopherson
2018-09-06 14:18       ` Sean Christopherson
2018-09-06 14:44         ` Borislav Petkov
2018-09-06 18:37         ` Brijesh Singh
2018-09-06 18:47           ` Sean Christopherson
2018-09-06 19:24             ` Brijesh Singh
2018-09-06 19:46               ` Brijesh Singh
2018-09-06 19:47               ` Sean Christopherson
2018-09-06 20:20                 ` Brijesh Singh
2018-09-06 20:39                   ` Sean Christopherson
2018-09-06 21:56                     ` Brijesh Singh
2018-09-06 14:43       ` Borislav Petkov
2018-09-06 14:56         ` Sean Christopherson
2018-09-06 15:19           ` Borislav Petkov
2018-09-06 15:54             ` Sean Christopherson
2018-09-06 18:33               ` Borislav Petkov
2018-09-06 18:43                 ` Brijesh Singh
2018-09-06 18:45                 ` Sean Christopherson [this message]
2018-09-06 19:03                   ` Borislav Petkov
2018-09-06 17:50       ` Brijesh Singh
2018-09-06 14:07   ` Sean Christopherson
2018-09-06 18:50     ` Brijesh Singh
2018-09-07  3:57       ` Brijesh Singh

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