From: Dave Hansen <dave.hansen@intel.com>
To: David Woodhouse <dwmw2@infradead.org>,
Nathan Chancellor <nathan@kernel.org>
Cc: "Ning, Hongyu" <hongyu.ning@linux.intel.com>,
kexec@lists.infradead.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Kai Huang <kai.huang@intel.com>,
Nikolay Borisov <nik.borisov@suse.com>,
linux-kernel@vger.kernel.org, Simon Horman <horms@kernel.org>,
Dave Young <dyoung@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
jpoimboe@kernel.org, bsz@amazon.de
Subject: Re: [PATCH] x86/kexec: Only write through identity mapping of control page
Date: Thu, 12 Dec 2024 13:18:10 -0800 [thread overview]
Message-ID: <4517cb69-3c5c-4e75-8a14-dab136b29c19@intel.com> (raw)
In-Reply-To: <9c68688625f409104b16164da30aa6d3eb494e5d.camel@infradead.org>
[-- Attachment #1: Type: text/plain, Size: 604 bytes --]
On 12/12/24 12:11, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
>
> The virtual mapping of the control page may have been _PAGE_GLOBAL and
> thus its PTE might not have been flushed on the %cr3 switch and it might
> effectively still be read-only. Move the writes to it down into the
> identity_mapped() function where the same %rip-relative addressing will
> get the new mapping.
>
> The stack is fine, as that's using the identity mapped address anyway.
Shouldn't we also ensure that Global entries don't bite anyone else?
Something like the completely untested attached patch?
[-- Attachment #2: pge.patch --]
[-- Type: text/x-patch, Size: 541 bytes --]
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index e9e88c342f752..ecbd77aab1221 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -155,6 +155,8 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
*/
andl $(X86_CR4_PAE | X86_CR4_LA57), %r13d
ALTERNATIVE "", __stringify(orl $X86_CR4_MCE, %r13d), X86_FEATURE_TDX_GUEST
+ /* Invalidate Global entries from the TLB: */
+ andq $~(X86_CR0_PGE), %r13d
movq %r13, %cr4
/* Flush the TLB (needed?) */
next prev parent reply other threads:[~2024-12-12 21:18 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-05 15:05 [PATCH v5 00/20] x86/kexec: Add exception handling for relocate_kernel and further yak-shaving David Woodhouse
2024-12-05 15:05 ` [PATCH v5 01/20] x86/kexec: Restore GDT on return from preserve_context kexec David Woodhouse
2024-12-05 15:05 ` [PATCH v5 02/20] x86/kexec: Clean up and document register use in relocate_kernel_64.S David Woodhouse
2024-12-05 15:05 ` [PATCH v5 03/20] x86/kexec: Use named labels in swap_pages " David Woodhouse
2024-12-05 15:05 ` [PATCH v5 04/20] x86/kexec: Only swap pages for preserve_context mode David Woodhouse
2024-12-05 15:05 ` [PATCH v5 05/20] x86/kexec: Allocate PGD for x86_64 transition page tables separately David Woodhouse
2024-12-05 15:05 ` [PATCH v5 06/20] x86/kexec: Copy control page into place in machine_kexec_prepare() David Woodhouse
2024-12-05 15:05 ` [PATCH v5 07/20] x86/kexec: Invoke copy of relocate_kernel() instead of the original David Woodhouse
2024-12-14 23:08 ` Nathan Chancellor
2024-12-15 7:19 ` David Woodhouse
2024-12-15 10:09 ` David Woodhouse
2024-12-16 5:49 ` Nathan Chancellor
2024-12-16 8:13 ` David Woodhouse
2024-12-16 12:09 ` David Woodhouse
2024-12-17 12:03 ` David Woodhouse
2024-12-18 9:03 ` Josh Poimboeuf
2024-12-18 9:44 ` David Woodhouse
2024-12-18 21:23 ` Josh Poimboeuf
2024-12-18 22:27 ` David Woodhouse
2024-12-19 0:20 ` Josh Poimboeuf
2024-12-19 10:02 ` David Woodhouse
2024-12-19 22:28 ` Josh Poimboeuf
2024-12-05 15:05 ` [PATCH v5 08/20] x86/kexec: Move relocate_kernel to kernel .data section David Woodhouse
2024-12-05 15:05 ` [PATCH v5 09/20] x86/kexec: Add data section to relocate_kernel David Woodhouse
2024-12-05 15:05 ` [PATCH v5 10/20] x86/kexec: Drop page_list argument from relocate_kernel() David Woodhouse
2024-12-05 15:05 ` [PATCH v5 11/20] x86/kexec: Eliminate writes through kernel mapping of relocate_kernel page David Woodhouse
2024-12-05 15:05 ` [PATCH v5 12/20] x86/kexec: Clean up register usage in relocate_kernel() David Woodhouse
2024-12-05 15:05 ` [PATCH v5 13/20] x86/kexec: Mark relocate_kernel page as ROX instead of RWX David Woodhouse
2024-12-12 1:44 ` Nathan Chancellor
2024-12-12 10:30 ` David Woodhouse
2024-12-12 15:04 ` Nathan Chancellor
2024-12-12 17:00 ` David Woodhouse
2024-12-12 17:42 ` Nathan Chancellor
2024-12-12 19:31 ` David Woodhouse
2024-12-12 20:11 ` [PATCH] x86/kexec: Only write through identity mapping of control page David Woodhouse
2024-12-12 20:31 ` Nathan Chancellor
2024-12-12 21:18 ` Dave Hansen [this message]
2024-12-12 21:32 ` David Woodhouse
2024-12-12 21:43 ` Dave Hansen
2024-12-12 21:59 ` David Woodhouse
2024-12-12 23:08 ` [PATCH] x86/kexec: Disable global pages before writing to " David Woodhouse
2024-12-13 7:51 ` Ning, Hongyu
2024-12-13 6:47 ` [PATCH] x86/kexec: Only write through identity mapping of " Ning, Hongyu
2024-12-12 3:03 ` [PATCH v5 13/20] x86/kexec: Mark relocate_kernel page as ROX instead of RWX Ning, Hongyu
2024-12-12 10:13 ` David Woodhouse
2024-12-13 6:45 ` Ning, Hongyu
2024-12-13 7:01 ` David Woodhouse
2024-12-13 7:41 ` Ning, Hongyu
2024-12-05 15:05 ` [PATCH v5 14/20] x86/kexec: Add CONFIG_KEXEC_DEBUG option David Woodhouse
2024-12-05 15:05 ` [PATCH v5 15/20] x86/kexec: Debugging support: load a GDT David Woodhouse
2024-12-05 15:05 ` [PATCH v5 16/20] x86/kexec: Debugging support: Load an IDT and basic exception entry points David Woodhouse
2024-12-05 15:05 ` [PATCH v5 17/20] x86/kexec: Debugging support: Dump registers on exception David Woodhouse
2024-12-05 15:05 ` [PATCH v5 18/20] x86/kexec: Add 8250 serial port output David Woodhouse
2024-12-05 15:05 ` [PATCH v5 19/20] x86/kexec: Add 8250 MMIO " David Woodhouse
2024-12-05 15:05 ` [PATCH v5 20/20] [DO NOT MERGE] x86/kexec: Add int3 in kexec path for testing David Woodhouse
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