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Message-ID: <20240430130323.GAZjDsG00Xdhv5mv8W@fat_crate.local>
Date: Tue, 30 Apr 2024 15:03:23 +0200
From: Borislav Petkov <bp@...en8.de>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
"Rafael J. Wysocki" <rafael@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
Elena Reshetova <elena.reshetova@...el.com>,
Jun Nakajima <jun.nakajima@...el.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
Tom Lendacky <thomas.lendacky@....com>,
"Kalra, Ashish" <ashish.kalra@....com>,
Sean Christopherson <seanjc@...gle.com>,
"Huang, Kai" <kai.huang@...el.com>, Baoquan He <bhe@...hat.com>,
kexec@...ts.infradead.org, linux-coco@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCHv10 05/18] x86/kexec: Keep CR4.MCE set during kexec for
TDX guest
On Tue, Apr 09, 2024 at 02:29:57PM +0300, Kirill A. Shutemov wrote:
> +1:
> + testq $X86_CR4_MCE, %r13
> + jz 1f
> + ALTERNATIVE "", __stringify(orl $X86_CR4_MCE, %eax), X86_FEATURE_TDX_GUEST
> 1:
Please add the below patch to your set. Those same-number labels are
just abominable.
Thx.
---
From: "Borislav Petkov (AMD)" <bp@...en8.de>
Date: Tue, 30 Apr 2024 15:00:16 +0200
Subject: [PATCH] x86/relocate_kernel: Use named labels for less confusion
That identity_mapped() function was loving that "1" label to the point
of completely confusing its readers.
Use named labels in each place for clarity.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
---
arch/x86/kernel/relocate_kernel_64.S | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 8e2037d78a1f..0077c9e562a7 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -152,13 +152,15 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
*/
movl $X86_CR4_PAE, %eax
testq $X86_CR4_LA57, %r13
- jz 1f
+ jz no_la57
orl $X86_CR4_LA57, %eax
-1:
+no_la57:
+
testq $X86_CR4_MCE, %r13
- jz 1f
+ jz mca_off
ALTERNATIVE "", __stringify(orl $X86_CR4_MCE, %eax), X86_FEATURE_TDX_GUEST
-1:
+mca_off:
+
movq %rax, %cr4
jmp 1f
@@ -173,9 +175,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
* used by kexec. Flush the caches before copying the kernel.
*/
testq %r12, %r12
- jz 1f
+ jz sme_off
wbinvd
-1:
+sme_off:
movq %rcx, %r11
call swap_pages
@@ -195,7 +197,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
*/
testq %r11, %r11
- jnz 1f
+ jnz relocate
xorl %eax, %eax
xorl %ebx, %ebx
xorl %ecx, %ecx
@@ -216,7 +218,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
ret
int3
-1:
+relocate:
popq %rdx
leaq PAGE_SIZE(%r10), %rsp
ANNOTATE_RETPOLINE_SAFE
--
2.43.0
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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