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From: Brijesh Singh <brijesh.singh@amd.com>
To: Borislav Petkov <bp@suse.de>
Cc: brijesh.singh@amd.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>
Subject: Re: [Part1 PATCH v5 02/17] x86/mm: Add Secure Encrypted Virtualization (SEV) support
Date: Thu, 28 Sep 2017 13:48:48 -0500	[thread overview]
Message-ID: <abed199b-217e-65ba-8dfc-f2e7b71eeef5@amd.com> (raw)
In-Reply-To: <20170928090242.ber7gynwaldinafa@pd.tnic>

Hi Boris,

On 09/28/2017 04:02 AM, Borislav Petkov wrote:
...

>> +bool sev_active(void)
>> +{
>> +	return sme_me_mask && sev_enabled;
> 
> What I'm still missing is the chicken bit. I.e., to be able to boot with
> "mem_encrypt=smeonly" or so, which disables the SEV side but can still
> allow SME. For when SEV has issues and people want to disable it.
> 


Let me understand the ask, are you saying that we need a method to disable the SEV
feature from the host OS so that Hypervisor will not be able to create a SEV guest?
Because once a guest is booted with SEV feature, there is no way to disable the SEV
feature from the guest.

i.e if "mem_encrypt=smeonly" is set then we clear X86_FEATURE_SEV capability flag
defined in [1].

[1] https://marc.info/?l=linux-kernel&m=150585470323923&w=2


> You can do the patch ontop of those and send it as a reply to this
> thread - no need to wait to resend the whole thing again.
> 

  reply	other threads:[~2017-09-28 18:48 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-27 15:13 [Part1 PATCH v5 00/17] x86: Secure Encrypted Virtualization (AMD) Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 01/17] Documentation/x86: Add AMD Secure Encrypted Virtualization (SEV) description Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 02/17] x86/mm: Add Secure Encrypted Virtualization (SEV) support Brijesh Singh
2017-09-28  9:02   ` Borislav Petkov
2017-09-28 18:48     ` Brijesh Singh [this message]
2017-09-28 19:23       ` Borislav Petkov
2017-09-29 12:28         ` Brijesh Singh
2017-09-29 14:41           ` Borislav Petkov
2017-09-29 15:54             ` Brijesh Singh
2017-09-29 15:56               ` Borislav Petkov
2017-09-29 23:06     ` [Part1 PATCH v5 18/18] x86/mm: add 'sme' argument in mem_encrypt= Brijesh Singh
2017-09-30 11:56       ` [PATCH] x86/CPU/AMD, mm: Extend with mem_encrypt=sme option Borislav Petkov
2017-09-30 21:17         ` Brijesh Singh
2017-09-30 21:41           ` Borislav Petkov
2017-10-01 17:00             ` Brijesh Singh
2017-10-01 17:16               ` Borislav Petkov
2017-10-01 19:45                 ` Brijesh Singh
2017-10-01 22:02                   ` Borislav Petkov
2017-10-02 11:32                     ` Brijesh Singh
2017-10-02 12:41                       ` Borislav Petkov
2017-10-02 15:07                         ` Brijesh Singh
2017-10-03 10:50                           ` Paolo Bonzini
2017-10-03 11:20                             ` Borislav Petkov
2017-10-02 13:44                 ` Tom Lendacky
2017-10-02 13:51                   ` Borislav Petkov
2017-10-02 16:35                     ` Tom Lendacky
2017-10-03 11:29                       ` Borislav Petkov
2017-09-27 15:13 ` [Part1 PATCH v5 03/17] x86/mm: Don't attempt to encrypt initrd under SEV Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 04/17] x86/realmode: Don't decrypt trampoline area " Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 05/17] x86/mm: Use encrypted access of boot related data with SEV Brijesh Singh
2017-09-28 11:13   ` Borislav Petkov
2017-09-28 16:20   ` [Part1 PATCH v5.1 " Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 06/17] x86/mm: Include SEV for encryption memory attribute changes Brijesh Singh
2017-09-27 15:53   ` Brijesh Singh
2017-09-27 17:26     ` Borislav Petkov
2017-09-27 19:17   ` [Part1 PATCH v5.1 " Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 07/17] x86/efi: Access EFI data as encrypted when SEV is active Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 08/17] resource: Consolidate resource walking code Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 09/17] resource: Provide resource struct in resource walk callback Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 10/17] x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory pages Brijesh Singh
2017-09-28 16:23   ` Borislav Petkov
2017-09-27 15:13 ` [Part1 PATCH v5 11/17] x86/mm: Add DMA support for SEV memory encryption Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 12/17] x86/boot: Add early boot support when running with SEV active Brijesh Singh
2017-09-28 17:02   ` Borislav Petkov
2017-09-27 15:13 ` [Part1 PATCH v5 13/17] x86/io: Unroll string I/O when SEV is active Brijesh Singh
2017-09-28 17:51   ` Borislav Petkov
2017-09-27 15:13 ` [Part1 PATCH v5 14/17] x86: Add support for changing memory encryption attribute in early boot Brijesh Singh
2017-09-27 15:13 ` [Part1 PATCH v5 15/17] percpu: Introduce DEFINE_PER_CPU_DECRYPTED Brijesh Singh
2017-09-28 20:32   ` Borislav Petkov
2017-09-27 15:13 ` [Part1 PATCH v5 16/17] X86/KVM: Decrypt shared per-cpu variables when SEV is active Brijesh Singh
2017-09-29  5:51   ` Borislav Petkov
2017-09-27 15:13 ` [Part1 PATCH v5 17/17] X86/KVM: Clear encryption attribute " Brijesh Singh
2017-09-29  6:26 ` [Part1 PATCH v5 00/17] x86: Secure Encrypted Virtualization (AMD) Borislav Petkov

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