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From: Borislav Petkov <bp@alien8.de>
To: Juergen Gross <jgross@suse.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	lists@nerdbynature.de, mikelley@microsoft.com,
	torvalds@linux-foundation.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v2 2/8] x86/mtrr: support setting MTRR state for software defined MTRRs
Date: Mon, 13 Feb 2023 16:03:07 +0100	[thread overview]
Message-ID: <Y+pRK6a419jenR9R@zn.tnic> (raw)
In-Reply-To: <6257114d-a957-f586-145c-d2a885417360@suse.com>

On Mon, Feb 13, 2023 at 03:07:07PM +0100, Juergen Gross wrote:
> Fixed in the sense of static.

Well, you can't use "fixed" to say "static" when former means something
very specific already in MTRR land.

> Wouldn't !cpu_feature_enabled(X86_FEATURE_HYPERVISOR) be enough?
> 
> I'm not sure we won't need that for TDX guests, too.

See, that's the problem. I wanna have it simple too. Lemme check with
dhansen.

> Yes, it is only relevant for PV dom0.

Right, I was asking whether "PV dom0" == X86_FEATURE_XENPV?

:)

> The number of fixed MTRRs is not dynamic AFAIK.

But nothing guarantees that the caller would pass an array "mtrr_type
*fixed" of size MTRR_NUM_FIXED_RANGES, right?

> A single interface makes it easier to avoid multiple calls.
> 
> In the end I'm fine with either way.

Yeah, I know. Question is, how much of this functionality will be
needed/used so that we can go all out on the interface design or we can
do a single one and forget about it...

> > Can Xen use x86_hyper_type() too?
> 
> It does.

Then pls add a x86_hyper_type check too to make sure a potential move of
this call is caught in the future.

Thx.

-- 
Regards/Gruss,
    Boris.

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

  reply	other threads:[~2023-02-13 15:03 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-09  7:22 [PATCH v2 0/8] x86/mtrr: fix handling with PAT but without MTRR Juergen Gross
2023-02-09  7:22 ` [PATCH v2 1/8] x86/mtrr: split off physical address size calculation Juergen Gross
2023-02-11 10:08   ` Borislav Petkov
2023-02-13  6:19     ` Juergen Gross
2023-02-09  7:22 ` [PATCH v2 2/8] x86/mtrr: support setting MTRR state for software defined MTRRs Juergen Gross
2023-02-13  1:07   ` Michael Kelley (LINUX)
2023-02-13  6:27     ` Juergen Gross
2023-02-13  6:43       ` Michael Kelley (LINUX)
2023-02-13 11:39   ` Borislav Petkov
2023-02-13 14:07     ` Juergen Gross
2023-02-13 15:03       ` Borislav Petkov [this message]
2023-02-13 15:11         ` Borislav Petkov
2023-02-13 15:18           ` Juergen Gross
2023-02-13 15:40             ` Borislav Petkov
2023-02-13 15:44               ` Juergen Gross
2023-02-13 18:53                 ` Borislav Petkov
2023-02-14  7:04                   ` Juergen Gross
2023-02-14  8:58                     ` Borislav Petkov
2023-02-14  9:02                       ` Juergen Gross
2023-02-14  9:10                         ` Borislav Petkov
2023-02-14  9:17                           ` Juergen Gross
2023-02-14  9:32                             ` Borislav Petkov
2023-02-13 15:27           ` Dave Hansen
2023-02-13 15:38             ` Juergen Gross
2023-02-13 15:36         ` Juergen Gross
2023-02-13 18:43           ` Borislav Petkov
2023-02-14  7:01             ` Juergen Gross
2023-02-14  0:45       ` Kirill A. Shutemov
2023-02-16  9:32     ` Juergen Gross
2023-02-16 11:02       ` Jeremi Piotrowski
2023-02-16 11:25       ` Borislav Petkov
2023-02-16 12:19         ` Juergen Gross
2023-02-16 12:29           ` Borislav Petkov
2023-02-16 16:04             ` Michael Kelley (LINUX)
2023-02-16 11:07     ` Jeremi Piotrowski
2023-02-16 11:27       ` Borislav Petkov
2023-02-09  7:22 ` [PATCH v2 3/8] x86/hyperv: set MTRR state when running as SEV-SNP Hyper-V guest Juergen Gross
2023-02-13  1:07   ` Michael Kelley (LINUX)
2023-02-13  6:28     ` Juergen Gross
2023-02-09  7:22 ` [PATCH v2 4/8] x86/xen: set MTRR state when running as Xen PV initial domain Juergen Gross
2023-02-09  7:22 ` [PATCH v2 5/8] x86/mtrr: revert commit 90b926e68f50 Juergen Gross
2023-02-10 18:59   ` Linux regression tracking (Thorsten Leemhuis)
2023-02-13  6:07     ` Juergen Gross
2023-02-13 11:46       ` Christian Kujau
2023-02-13 16:23         ` Juergen Gross
2023-02-13 17:01           ` Michael Kelley (LINUX)
2023-02-13 17:24             ` Juergen Gross
2023-02-13 22:54           ` Christian Kujau
2023-02-14  7:13             ` Juergen Gross
2023-02-09  7:22 ` [PATCH v2 6/8] x86/mtrr: don't let mtrr_type_lookup() return MTRR_TYPE_INVALID Juergen Gross
2023-02-09  7:22 ` [PATCH v2 7/8] x86/mm: only check uniform after calling mtrr_type_lookup() Juergen Gross
2023-02-11  0:06   ` Edgecombe, Rick P
2023-02-13  6:08     ` Juergen Gross
2023-02-13  1:08   ` Michael Kelley (LINUX)
2023-02-13  6:35     ` Juergen Gross
2023-02-15 13:40     ` Juergen Gross
2023-02-15 19:38       ` Michael Kelley (LINUX)
2023-02-16  5:22         ` Juergen Gross
2023-02-09  7:22 ` [PATCH v2 8/8] x86/mtrr: drop sanity check in mtrr_type_lookup_fixed() Juergen Gross
2023-02-11  0:06 ` [PATCH v2 0/8] x86/mtrr: fix handling with PAT but without MTRR Edgecombe, Rick P
2023-02-13  6:12   ` Juergen Gross
2023-02-13 18:21     ` Edgecombe, Rick P
2023-02-15  8:25       ` Juergen Gross
2023-02-15 23:22         ` Linus Torvalds
2023-02-16  5:35           ` Juergen Gross

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