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Message-ID: <YcHQJqm4iP9/9TjE@zn.tnic>
Date: Tue, 21 Dec 2021 14:01:26 +0100
From: Borislav Petkov <bp@...en8.de>
To: Brijesh Singh <brijesh.singh@....com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
linux-efi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
linux-coco@...ts.linux.dev, linux-mm@...ck.org,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
Tom Lendacky <thomas.lendacky@....com>,
"H. Peter Anvin" <hpa@...or.com>, Ard Biesheuvel <ardb@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Jim Mattson <jmattson@...gle.com>,
Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Sergio Lopez <slp@...hat.com>, Peter Gonda <pgonda@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
David Rientjes <rientjes@...gle.com>,
Dov Murik <dovmurik@...ux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@....com>,
Michael Roth <michael.roth@....com>,
Vlastimil Babka <vbabka@...e.cz>,
"Kirill A . Shutemov" <kirill@...temov.name>,
Andi Kleen <ak@...ux.intel.com>,
"Dr . David Alan Gilbert" <dgilbert@...hat.com>,
tony.luck@...el.com, marcorr@...gle.com,
sathyanarayanan.kuppuswamy@...ux.intel.com
Subject: Re: [PATCH v8 09/40] x86/compressed: Add helper for validating pages
in the decompression stage
On Fri, Dec 10, 2021 at 09:43:01AM -0600, Brijesh Singh wrote:
> diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
> index f7213d0943b8..ef77453cc629 100644
> --- a/arch/x86/boot/compressed/ident_map_64.c
> +++ b/arch/x86/boot/compressed/ident_map_64.c
> @@ -275,15 +275,31 @@ static int set_clr_page_flags(struct x86_mapping_info *info,
> * Changing encryption attributes of a page requires to flush it from
> * the caches.
> */
> - if ((set | clr) & _PAGE_ENC)
> + if ((set | clr) & _PAGE_ENC) {
> clflush_page(address);
>
> + /*
> + * If the encryption attribute is being cleared, then change
> + * the page state to shared in the RMP table.
> + */
> + if (clr)
> + snp_set_page_shared(pte_pfn(*ptep) << PAGE_SHIFT);
You forgot to change that one.
> + }
> +
> /* Update PTE */
> pte = *ptep;
> pte = pte_set_flags(pte, set);
> pte = pte_clear_flags(pte, clr);
> set_pte(ptep, pte);
>
> + /*
> + * If the encryption attribute is being set, then change the page state to
> + * private in the RMP entry. The page state must be done after the PTE
^
change
Geez, tell me, why should I be even bothering to review stuff if I have
to go look at the previous review I did and find that you haven't really
addressed it?!
> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
> index 7ac5842e32b6..a2f956cfafba 100644
> --- a/arch/x86/include/asm/sev-common.h
> +++ b/arch/x86/include/asm/sev-common.h
> @@ -57,6 +57,32 @@
> #define GHCB_MSR_AP_RESET_HOLD_REQ 0x006
> #define GHCB_MSR_AP_RESET_HOLD_RESP 0x007
>
> +/*
> + * SNP Page State Change Operation
> + *
> + * GHCBData[55:52] - Page operation:
> + * 0x0001 – Page assignment, Private
> + * 0x0002 – Page assignment, Shared
I wonder how you've achieved that:
massage_diff: Warning: Unicode char [–] (0x2013) in line: + * 0x0001 – Page assignment, Private
massage_diff: Warning: Unicode char [–] (0x2013) in line: + * 0x0002 – Page assignment, Shared
See https://trojansource.codes/ for some background.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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