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From: Borislav Petkov <bp@alien8.de>
To: "Michael Kelley (LINUX)" <mikelley@microsoft.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Dave Hansen <dave.hansen@intel.com>,
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Subject: Re: [PATCH v5 06/14] x86/ioremap: Support hypervisor specified range to map as encrypted
Date: Fri, 10 Feb 2023 20:36:44 +0100	[thread overview]
Message-ID: <Y+aczIbbQm/ZNunZ@zn.tnic> (raw)
In-Reply-To: <BYAPR21MB16882083E84F20B906E2C847D7DE9@BYAPR21MB1688.namprd21.prod.outlook.com>

On Fri, Feb 10, 2023 at 07:15:41PM +0000, Michael Kelley (LINUX) wrote:
> FWIW, I don't think the list of devices to be accessed encrypted is likely
> to grow significantly.  Is one or two more possible?  Perhaps.  Does it
> become a list of ten?  I doubt it.

What happens if the next silly HV guest scheme comes along and they do
need more and different ones?

Do I say, but but, Michael said that he doubted at the time that that
list would grow... ;-\

And then all our paths are sprinkled with

	if (cc_platform_has())

and we can't change sh*t anymore out of fear that some weird guest type
will break.

> One approach is to go with the individual device attributes for now.
> If the list does grow significantly, there will probably be patterns
> or groupings that we can't discern now.  We could restructure into
> larger buckets at that point based on those patterns/groupings.

There's a reason the word "platform" is in cc_platform_has(). Initially
we wanted to distinguish attributes of the different platforms. So even
if y'all don't like CC_ATTR_PARAVISOR, that is what distinguishes this
platform and it *is* one platform.

So call it CC_ATTR_SEV_VTOM as it uses that technology or whatever. But
call it like the platform, not to mean "I need this functionality".

And yes, we could do the regroupings later because, yeah, those things
are not exposed to userspace so it's not like they're cast in stone but
I fear that we will do regroupings and we will break guests.

Now if you had CC_ATTR_<PLATFORM_TYPE> then you break (or not) only that
platform.

Oh, and then there's the thing that this is kernel proper - that code
still runs on real hardware, for now, and is not only guests. And not
everything is a damn cloud.

So I don't want a zoo here and we'd have to agree to distinguish by
platform and not by different functionality required.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2023-02-10 19:37 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-12 21:42 [PATCH v5 00/14] Add PCI pass-thru support to Hyper-V Confidential VMs Michael Kelley
2023-01-12 21:42 ` [PATCH v5 01/14] x86/ioapic: Gate decrypted mapping on cc_platform_has() attribute Michael Kelley
2023-01-12 21:42 ` [PATCH v5 02/14] x86/hyperv: Reorder code to facilitate future work Michael Kelley
2023-01-12 21:42 ` [PATCH v5 03/14] Drivers: hv: Explicitly request decrypted in vmap_pfn() calls Michael Kelley
2023-01-12 21:42 ` [PATCH v5 04/14] x86/mm: Handle decryption/re-encryption of bss_decrypted consistently Michael Kelley
2023-01-12 21:42 ` [PATCH v5 05/14] init: Call mem_encrypt_init() after Hyper-V hypercall init is done Michael Kelley
2023-01-12 21:42 ` [PATCH v5 06/14] x86/ioremap: Support hypervisor specified range to map as encrypted Michael Kelley
2023-01-20 20:15   ` Borislav Petkov
2023-01-21  4:10     ` Michael Kelley (LINUX)
2023-01-25 14:55       ` Borislav Petkov
2023-02-02  5:49         ` Michael Kelley (LINUX)
2023-02-07 12:41           ` Borislav Petkov
2023-02-07 19:01             ` Michael Kelley (LINUX)
2023-02-07 19:33               ` Borislav Petkov
2023-02-07 19:48                 ` Michael Kelley (LINUX)
2023-02-07 19:54                   ` Borislav Petkov
2023-02-07 19:57                     ` Michael Kelley (LINUX)
2023-02-08  0:18                     ` Michael Kelley (LINUX)
2023-02-08 15:09                       ` Dave Hansen
2023-02-09 17:29                         ` Michael Kelley (LINUX)
2023-02-08 17:23             ` Dave Hansen
2023-02-09 17:47               ` Michael Kelley (LINUX)
2023-02-10 18:41                 ` Sean Christopherson
2023-02-10 18:58                   ` Dave Hansen
2023-02-10 19:03                   ` Borislav Petkov
2023-02-10 19:15                     ` Michael Kelley (LINUX)
2023-02-10 19:36                       ` Borislav Petkov [this message]
2023-02-10 19:58                         ` Dave Hansen
2023-02-10 20:50                           ` Sean Christopherson
2023-02-10 20:57                             ` Sean Christopherson
2023-02-10 21:27                               ` Michael Kelley (LINUX)
2023-02-10 23:47                                 ` Sean Christopherson
2023-02-14  7:45                                   ` Michael Kelley (LINUX)
2023-02-16 13:32                                   ` Borislav Petkov
2023-02-16 16:16                                     ` Michael Kelley (LINUX)
2023-02-16 17:06                                       ` Borislav Petkov
2023-02-17  6:16                                         ` Michael Kelley (LINUX)
2023-02-17 14:55                                           ` Borislav Petkov
2023-02-22 22:13                                             ` Sean Christopherson
2023-02-22 22:33                                               ` Borislav Petkov
2023-02-22 22:54                                                 ` Sean Christopherson
2023-02-22 23:34                                                   ` Borislav Petkov
2023-02-23  1:21                                                     ` Sean Christopherson
2023-02-23 10:45                                                       ` Borislav Petkov
2023-02-23 20:01                                                         ` Michael Kelley (LINUX)
2023-02-23 20:27                                                           ` Dave Hansen
2023-03-06 21:51                                                             ` Borislav Petkov
2023-03-09 11:12                                                               ` David Woodhouse
2023-03-09 11:59                                                                 ` Borislav Petkov
2023-03-09 13:00                                                                   ` David Woodhouse
2023-03-09 14:19                                                                   ` Tom Lendacky
2023-03-09 14:36                                                                     ` Jörg Rödel
2023-03-09 14:45                                                                       ` Borislav Petkov
2023-03-09 15:45                                                                         ` David Woodhouse
2023-03-09 16:34                                                                           ` Borislav Petkov
2023-03-10 10:05                                                                             ` David Woodhouse
2023-02-23 20:26                                   ` Dave Hansen
2023-02-23 20:41                                     ` Dave Hansen
2023-02-23 20:51                                       ` Michael Kelley (LINUX)
2023-02-23 21:07                                         ` Sean Christopherson
2023-02-23 21:15                                           ` Michael Kelley (LINUX)
2023-02-23 21:24                                             ` Dave Hansen
2023-01-12 21:42 ` [PATCH v5 07/14] x86/hyperv: Change vTOM handling to use standard coco mechanisms Michael Kelley
2023-01-12 21:42 ` [PATCH v5 08/14] swiotlb: Remove bounce buffer remapping for Hyper-V Michael Kelley
2023-01-12 21:42 ` [PATCH v5 09/14] Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages Michael Kelley
2023-01-12 21:42 ` [PATCH v5 10/14] Drivers: hv: vmbus: Remove second way of mapping ring buffers Michael Kelley
2023-01-12 21:42 ` [PATCH v5 11/14] hv_netvsc: Remove second mapping of send and recv buffers Michael Kelley
2023-01-12 21:42 ` [PATCH v5 12/14] Drivers: hv: Don't remap addresses that are above shared_gpa_boundary Michael Kelley
2023-01-12 21:42 ` [PATCH v5 13/14] PCI: hv: Add hypercalls to read/write MMIO space Michael Kelley
2023-01-12 21:42 ` [PATCH v5 14/14] PCI: hv: Enable PCI pass-thru devices in Confidential VMs Michael Kelley

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