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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: 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
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kuppuswamy Sathyanarayanan
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Elena Reshetova <elena.reshetova@intel.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	Rick Edgecombe  <rick.p.edgecombe@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"Kalra, Ashish" <ashish.kalra@amd.com>,
	Sean Christopherson <seanjc@google.com>,
	"Huang, Kai" <kai.huang@intel.com>, Baoquan He <bhe@redhat.com>,
	kexec@lists.infradead.org, linux-coco@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv5 06/16] x86/kexec: Keep CR4.MCE set during kexec for TDX guest
Date: Sat, 23 Dec 2023 02:51:58 +0300	[thread overview]
Message-ID: <20231222235209.32143-7-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20231222235209.32143-1-kirill.shutemov@linux.intel.com>

TDX guests are not allowed to clear CR4.MCE. Attempt to clear it leads
to #VE.

Use alternatives to keep the flag during kexec for TDX guests.

The change doesn't affect non-TDX-guest environments.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
---
 arch/x86/kernel/relocate_kernel_64.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 56cab1bb25f5..e144bcf60cbe 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -5,6 +5,8 @@
  */
 
 #include <linux/linkage.h>
+#include <linux/stringify.h>
+#include <asm/alternative.h>
 #include <asm/page_types.h>
 #include <asm/kexec.h>
 #include <asm/processor-flags.h>
@@ -145,12 +147,15 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
 	 * Set cr4 to a known state:
 	 *  - physical address extension enabled
 	 *  - 5-level paging, if it was enabled before
+	 *  - Machine check exception on TDX guest. Clearing MCE is not allowed
+	 *    in TDX guests.
 	 */
 	movl	$X86_CR4_PAE, %eax
 	testq	$X86_CR4_LA57, %r13
 	jz	1f
 	orl	$X86_CR4_LA57, %eax
 1:
+	ALTERNATIVE "", __stringify(orl $X86_CR4_MCE, %eax), X86_FEATURE_TDX_GUEST
 	movq	%rax, %cr4
 
 	jmp 1f
-- 
2.41.0


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  parent reply	other threads:[~2023-12-22 23:52 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-22 23:51 [PATCHv5 00/16] x86/tdx: Add kexec support Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 01/16] x86/acpi: Extract ACPI MADT wakeup code into a separate file Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 02/16] x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 03/16] cpu/hotplug: Add support for declaring CPU offlining not supported Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 04/16] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Kirill A. Shutemov
2023-12-22 23:51 ` [PATCHv5 05/16] x86/kvm: Do not try to disable kvmclock if it was not enabled Kirill A. Shutemov
2023-12-22 23:51 ` Kirill A. Shutemov [this message]
2023-12-22 23:51 ` [PATCHv5 07/16] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 08/16] x86/mm: Return correct level from lookup_address() if pte is none Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 09/16] x86/tdx: Account shared memory Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 10/16] x86/tdx: Convert shared memory back to private on kexec Kirill A. Shutemov
2024-01-05 19:38   ` Edgecombe, Rick P
2024-01-06  0:59     ` kirill.shutemov
2024-01-06  1:12       ` Edgecombe, Rick P
2024-01-15 10:53   ` Nikolay Borisov
2024-01-16  7:28     ` Kirill A. Shutemov
2024-01-16  8:01       ` Nikolay Borisov
2024-01-16 10:45         ` Kirill A. Shutemov
2024-01-16 10:53       ` Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 11/16] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 12/16] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 13/16] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case Kirill A. Shutemov
2023-12-22 23:52 ` [PATCHv5 14/16] x86/smp: Add smp_ops.stop_this_cpu() callback Kirill A. Shutemov
2023-12-25  8:05   ` [PATCHv5.1 " Kirill A. Shutemov
2024-01-08  3:04     ` Huang, Kai
2024-01-08 10:15       ` kirill.shutemov
2024-01-09  3:04         ` Huang, Kai
2023-12-22 23:52 ` [PATCHv5 15/16] x86/mm: Introduce kernel_ident_mapping_free() Kirill A. Shutemov
2024-01-08  3:13   ` Huang, Kai
2024-01-08  3:30     ` Huang, Kai
2024-01-08 10:17       ` kirill.shutemov
2024-01-08 13:13         ` Huang, Kai
2024-01-08 13:35           ` kirill.shutemov
2023-12-22 23:52 ` [PATCHv5 16/16] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Kirill A. Shutemov
2024-01-15 13:19   ` Nikolay Borisov
2024-01-16  6:50     ` Kirill A. Shutemov

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