Re: [PATCH v1 11/26] x86/sev: Invalidate pages from the direct map when adding them to the RMP table
From: Borislav Petkov <bp@alien8.de>
Date: 2024-01-15 09:02:21
Also in:
kvm, linux-crypto, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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