From: "Huang, Kai" <kai.huang@intel.com>
To: "kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"x86@kernel.org" <x86@kernel.org>, "bp@alien8.de" <bp@alien8.de>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"rafael@kernel.org" <rafael@kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"Hunter, Adrian" <adrian.hunter@intel.com>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
"ashish.kalra@amd.com" <ashish.kalra@amd.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"seanjc@google.com" <seanjc@google.com>,
"bhe@redhat.com" <bhe@redhat.com>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>
Subject: Re: [PATCHv4 06/14] x86/kexec: Keep CR4.MCE set during kexec for TDX guest
Date: Tue, 5 Dec 2023 23:58:45 +0000 [thread overview]
Message-ID: <861f583e2550959616e19565235f0debbe27149b.camel@intel.com> (raw)
In-Reply-To: <20231205004510.27164-7-kirill.shutemov@linux.intel.com>
On Tue, 2023-12-05 at 03:45 +0300, Kirill A. Shutemov wrote:
> 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 | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
> index 56cab1bb25f5..cd6a53667c6b 100644
> --- a/arch/x86/kernel/relocate_kernel_64.S
> +++ b/arch/x86/kernel/relocate_kernel_64.S
> @@ -145,12 +145,15 @@ 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
Nit:
It seems <asm/alternative.h> isn't included in relocate_kernel_64.S. Maybe it's
better to do it explicitly.
Maybe even better to explicitly include <linux/stringify.h> too, but I see
<asm/alternative.h> already does that.
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next prev parent reply other threads:[~2023-12-05 23:59 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 0:44 [PATCHv4 00/14] x86/tdx: Add kexec support Kirill A. Shutemov
2023-12-05 0:44 ` [PATCHv4 01/14] x86/acpi: Extract ACPI MADT wakeup code into a separate file Kirill A. Shutemov
2023-12-05 0:44 ` [PATCHv4 02/14] x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init Kirill A. Shutemov
2023-12-05 0:44 ` [PATCHv4 03/14] cpu/hotplug: Add support for declaring CPU offlining not supported Kirill A. Shutemov
2023-12-15 19:42 ` Thomas Gleixner
2023-12-05 0:45 ` [PATCHv4 04/14] cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup Kirill A. Shutemov
2023-12-15 19:43 ` Thomas Gleixner
2023-12-05 0:45 ` [PATCHv4 05/14] x86/kvm: Do not try to disable kvmclock if it was not enabled Kirill A. Shutemov
2023-12-11 23:10 ` Kirill A. Shutemov
2023-12-13 17:22 ` Sean Christopherson
2024-01-04 15:05 ` Kirill A. Shutemov
2024-01-09 14:59 ` Sean Christopherson
2023-12-05 0:45 ` [PATCHv4 06/14] x86/kexec: Keep CR4.MCE set during kexec for TDX guest Kirill A. Shutemov
2023-12-05 23:58 ` Huang, Kai [this message]
2023-12-06 13:26 ` kirill.shutemov
2023-12-05 0:45 ` [PATCHv4 07/14] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 08/14] x86/mm: Return correct level from lookup_address() if pte is none Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 09/14] x86/tdx: Account shared memory Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 10/14] x86/tdx: Convert shared memory back to private on kexec Kirill A. Shutemov
2023-12-06 1:28 ` Edgecombe, Rick P
2023-12-06 15:07 ` kirill.shutemov
2023-12-06 18:32 ` Edgecombe, Rick P
2023-12-05 0:45 ` [PATCHv4 11/14] x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 12/14] x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure Kirill A. Shutemov
2023-12-05 0:45 ` [PATCHv4 13/14] x86/acpi: Do not attempt to bring up secondary CPUs in kexec case Kirill A. Shutemov
2023-12-15 20:08 ` Thomas Gleixner
2023-12-05 0:45 ` [PATCHv4 14/14] x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method Kirill A. Shutemov
2023-12-05 23:36 ` Huang, Kai
2023-12-22 11:19 ` kirill.shutemov
2023-12-22 11:38 ` Huang, Kai
2023-12-15 20:29 ` Thomas Gleixner
2023-12-22 16:34 ` Kirill A. Shutemov
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