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Message-ID: <20240115090126.GEZaT0ZnSPIPsnUiyt@fat_crate.local>
Date: Mon, 15 Jan 2024 10:01:26 +0100
From: Borislav Petkov <bp@...en8.de>
To: Michael Roth <michael.roth@....com>
Cc: x86@...nel.org, kvm@...r.kernel.org, linux-coco@...ts.linux.dev,
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Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v1 11/26] x86/sev: Invalidate pages from the direct map
when adding them to the RMP table
On Sat, Dec 30, 2023 at 10:19:39AM -0600, Michael Roth wrote:
> + /*
> + * If the kernel uses a 2MB directmap mapping to write to an address,
> + * and that 2MB range happens to contain a 4KB page that set to private
> + * in the RMP table, an RMP #PF will trigger and cause a host crash.
Also:
diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c
index 7d294d1a620b..2ad83e7fb2da 100644
--- a/arch/x86/virt/svm/sev.c
+++ b/arch/x86/virt/svm/sev.c
@@ -415,8 +415,9 @@ static int rmpupdate(u64 pfn, struct rmp_state *state)
/*
* If the kernel uses a 2MB directmap mapping to write to an address,
- * and that 2MB range happens to contain a 4KB page that set to private
- * in the RMP table, an RMP #PF will trigger and cause a host crash.
+ * and that 2MB range happens to contain a 4KB page that has been set
+ * to private in the RMP table, an RMP #PF will trigger and cause a
+ * host crash.
*
* Prevent this by removing pages from the directmap prior to setting
* them as private in the RMP table.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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