From: Tom Lendacky <thomas.lendacky@amd.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Sean Christopherson <seanjc@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, David Woodhouse <dwmw2@infradead.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Brian Gerst <brgerst@gmail.com>,
Arjan van de Veen <arjan@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Paul McKenney <paulmck@kernel.org>,
Oleksandr Natalenko <oleksandr@natalenko.name>,
Paul Menzel <pmenzel@molgen.mpg.de>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Piotr Gorski <lucjan.lucjanov@gmail.com>,
Usama Arif <usama.arif@bytedance.com>,
Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
xen-devel@lists.xenproject.org,
Russell King <linux@armlinux.org.uk>,
Arnd Bergmann <arnd@arndb.de>,
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Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Guo Ren <guoren@kernel.org>,
linux-csky@vger.kernel.org,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
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"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
Helge Deller <deller@gmx.de>,
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Mark Rutland <mark.rutland@arm.com>,
Sabin Rapan <sabrapan@amazon.com>,
"Michael Kelley (LINUX)" <mikelley@microsoft.com>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [patch] x86/smpboot: Disable parallel bootup if cc_vendor != NONE
Date: Tue, 30 May 2023 15:03:40 -0500 [thread overview]
Message-ID: <8751e955-e975-c6d4-630c-02912b9ef9da@amd.com> (raw)
In-Reply-To: <87leh5iom8.ffs@tglx>
On 5/30/23 14:51, Thomas Gleixner wrote:
> On Tue, May 30 2023 at 09:56, Sean Christopherson wrote:
>> On Tue, May 30, 2023, Thomas Gleixner wrote:
>>> On Tue, May 30 2023 at 15:29, Kirill A. Shutemov wrote:
>>>> On Tue, May 30, 2023 at 02:09:17PM +0200, Thomas Gleixner wrote:
>>>>> The decision to allow parallel bringup of secondary CPUs checks
>>>>> CC_ATTR_GUEST_STATE_ENCRYPT to detect encrypted guests. Those cannot use
>>>>> parallel bootup because accessing the local APIC is intercepted and raises
>>>>> a #VC or #VE, which cannot be handled at that point.
>>>>>
>>>>> The check works correctly, but only for AMD encrypted guests. TDX does not
>>>>> set that flag.
>>>>>
>>>>> Check for cc_vendor != CC_VENDOR_NONE instead. That might be overbroad, but
>>>>> definitely works for both AMD and Intel.
>>>>
>>>> It boots fine with TDX, but I think it is wrong. cc_get_vendor() will
>>>> report CC_VENDOR_AMD even on bare metal if SME is enabled. I don't think
>>>> we want it.
>>>
>>> Right. Did not think about that.
>>>
>>> But the same way is CC_ATTR_GUEST_MEM_ENCRYPT overbroad for AMD. Only
>>> SEV-ES traps RDMSR if I'm understandig that maze correctly.
>>
>> Ya, regular SEV doesn't encrypt register state.
>
> That aside. From a semantical POV making this decision about parallel
> bootup based on some magic CC encryption attribute is questionable.
>
> I'm tending to just do the below and make this CC agnostic (except that
> I couldn't find the right spot for SEV-ES to clear that flag.)
Maybe in sme_sev_setup_real_mode() in arch/x86/realmode/init.c? You could
clear the flag within the CC_ATTR_GUEST_STATE_ENCRYPT check.
Thanks,
Tom
>
> Thanks,
>
> tglx
> ---
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -871,5 +871,7 @@ void __init tdx_early_init(void)
> x86_platform.guest.enc_tlb_flush_required = tdx_tlb_flush_required;
> x86_platform.guest.enc_status_change_finish = tdx_enc_status_changed;
>
> + x86_cpuinit.parallel_bringup = false;
> +
> pr_info("Guest detected\n");
> }
> --- a/arch/x86/include/asm/x86_init.h
> +++ b/arch/x86/include/asm/x86_init.h
> @@ -2,6 +2,7 @@
> #ifndef _ASM_X86_PLATFORM_H
> #define _ASM_X86_PLATFORM_H
>
> +#include <linux/bits.h>
> #include <asm/bootparam.h>
>
> struct ghcb;
> @@ -177,11 +178,14 @@ struct x86_init_ops {
> * struct x86_cpuinit_ops - platform specific cpu hotplug setups
> * @setup_percpu_clockev: set up the per cpu clock event device
> * @early_percpu_clock_init: early init of the per cpu clock event device
> + * @fixup_cpu_id: fixup function for cpuinfo_x86::phys_proc_id
> + * @parallel_bringup: Parallel bringup control
> */
> struct x86_cpuinit_ops {
> void (*setup_percpu_clockev)(void);
> void (*early_percpu_clock_init)(void);
> void (*fixup_cpu_id)(struct cpuinfo_x86 *c, int node);
> + bool parallel_bringup;
> };
>
> struct timespec64;
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1287,6 +1287,11 @@ bool __init arch_cpuhp_init_parallel_bri
> return false;
> }
>
> + if (!x86_cpuinit.parallel_bringup) {
> + pr_info("Parallel CPU startup disabled by the platform\n");
> + return false;
> + }
> +
> smpboot_control = STARTUP_READ_APICID;
> pr_debug("Parallel CPU startup enabled: 0x%08x\n", smpboot_control);
> return true;
> --- a/arch/x86/kernel/x86_init.c
> +++ b/arch/x86/kernel/x86_init.c
> @@ -126,6 +126,7 @@ struct x86_init_ops x86_init __initdata
> struct x86_cpuinit_ops x86_cpuinit = {
> .early_percpu_clock_init = x86_init_noop,
> .setup_percpu_clockev = setup_secondary_APIC_clock,
> + .parallel_bringup = true,
> };
>
> static void default_nmi_init(void) { };
next prev parent reply other threads:[~2023-05-30 20:04 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-08 19:43 [patch v3 00/36] cpu/hotplug, x86: Reworked parallel CPU bringup Thomas Gleixner
2023-05-08 19:43 ` [patch v3 01/36] [patch V2 01/38] x86/smpboot: Cleanup topology_phys_to_logical_pkg()/die() Thomas Gleixner
2023-05-08 19:43 ` [patch v3 02/36] cpu/hotplug: Mark arch_disable_smp_support() and bringup_nonboot_cpus() __init Thomas Gleixner
2023-05-08 19:43 ` [patch v3 03/36] x86/smpboot: Avoid pointless delay calibration if TSC is synchronized Thomas Gleixner
2023-05-08 19:43 ` [patch v3 04/36] x86/smpboot: Rename start_cpu0() to soft_restart_cpu() Thomas Gleixner
2023-05-08 19:43 ` [patch v3 05/36] x86/topology: Remove CPU0 hotplug option Thomas Gleixner
2023-05-08 19:43 ` [patch v3 06/36] x86/smpboot: Remove the CPU0 hotplug kludge Thomas Gleixner
2023-05-08 19:43 ` [patch v3 07/36] x86/smpboot: Restrict soft_restart_cpu() to SEV Thomas Gleixner
2023-05-08 19:43 ` [patch v3 08/36] x86/smpboot: Split up native_cpu_up() into separate phases and document them Thomas Gleixner
2023-05-09 10:04 ` Peter Zijlstra
2023-05-09 12:07 ` Thomas Gleixner
2023-05-09 17:59 ` Thomas Gleixner
2023-05-09 20:11 ` Thomas Gleixner
2023-05-10 8:39 ` Peter Zijlstra
2023-05-09 10:19 ` Peter Zijlstra
2023-05-09 12:08 ` Thomas Gleixner
2023-05-09 18:03 ` Thomas Gleixner
2023-05-09 10:31 ` Peter Zijlstra
2023-05-09 12:09 ` Thomas Gleixner
2023-05-08 19:43 ` [patch v3 09/36] x86/smpboot: Get rid of cpu_init_secondary() Thomas Gleixner
2023-05-08 19:43 ` [patch v3 10/36] [patch V2 10/38] x86/cpu/cacheinfo: Remove cpu_callout_mask dependency Thomas Gleixner
2023-05-08 19:43 ` [patch v3 11/36] [patch V2 11/38] x86/smpboot: Move synchronization masks to SMP boot code Thomas Gleixner
2023-05-08 19:43 ` [patch v3 12/36] [patch V2 12/38] x86/smpboot: Make TSC synchronization function call based Thomas Gleixner
2023-05-08 19:43 ` [patch v3 13/36] x86/smpboot: Remove cpu_callin_mask Thomas Gleixner
2023-05-09 10:49 ` Peter Zijlstra
2023-05-09 12:09 ` Thomas Gleixner
2023-05-08 19:43 ` [patch v3 14/36] [patch V2 14/38] cpu/hotplug: Rework sparse_irq locking in bringup_cpu() Thomas Gleixner
2023-05-09 11:02 ` Peter Zijlstra
2023-05-09 12:10 ` Thomas Gleixner
2023-05-08 19:43 ` [patch v3 15/36] x86/smpboot: Remove wait for cpu_online() Thomas Gleixner
2023-05-08 19:43 ` [patch v3 16/36] x86/xen/smp_pv: Remove wait for CPU online Thomas Gleixner
2023-05-08 19:43 ` [patch v3 17/36] x86/xen/hvm: Get rid of DEAD_FROZEN handling Thomas Gleixner
2023-05-08 19:43 ` [patch v3 18/36] [patch V2 18/38] cpu/hotplug: Add CPU state tracking and synchronization Thomas Gleixner
2023-05-09 11:07 ` Peter Zijlstra
2023-05-09 11:35 ` Peter Zijlstra
2023-05-09 12:12 ` Thomas Gleixner
2023-05-08 19:43 ` [patch v3 19/36] x86/smpboot: Switch to hotplug core state synchronization Thomas Gleixner
2023-05-08 19:43 ` [patch v3 20/36] cpu/hotplug: Remove cpu_report_state() and related unused cruft Thomas Gleixner
2023-05-08 19:44 ` [patch v3 21/36] [patch V2 21/38] ARM: smp: Switch to hotplug core state synchronization Thomas Gleixner
2023-05-08 19:44 ` [patch v3 22/36] arm64: " Thomas Gleixner
2023-05-08 19:44 ` [patch v3 23/36] [patch V2 23/38] csky/smp: " Thomas Gleixner
2023-05-08 19:44 ` [patch v3 24/36] [patch V2 24/38] MIPS: SMP_CPS: " Thomas Gleixner
2023-05-08 19:44 ` [patch v3 25/36] parisc: " Thomas Gleixner
2023-05-08 19:44 ` [patch v3 26/36] riscv: " Thomas Gleixner
2023-05-08 19:44 ` [patch v3 27/36] cpu/hotplug: Remove unused state functions Thomas Gleixner
2023-05-08 19:44 ` [patch v3 28/36] cpu/hotplug: Reset task stack state in _cpu_up() Thomas Gleixner
2023-05-08 19:44 ` [patch v3 29/36] [patch V2 29/38] cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism Thomas Gleixner
2023-05-08 19:44 ` [patch v3 30/36] x86/smpboot: Enable split CPU startup Thomas Gleixner
2023-05-08 19:44 ` [patch v3 31/36] x86/apic: Provide cpu_primary_thread mask Thomas Gleixner
2023-05-24 20:48 ` Kirill A. Shutemov
2023-05-26 10:14 ` Thomas Gleixner
2023-05-27 13:40 ` Thomas Gleixner
2023-05-29 2:39 ` Kirill A. Shutemov
2023-05-29 19:27 ` Thomas Gleixner
2023-05-29 20:31 ` Kirill A. Shutemov
2023-05-30 0:54 ` Kirill A. Shutemov
2023-05-30 9:26 ` Thomas Gleixner
2023-05-30 10:34 ` Thomas Gleixner
2023-05-30 11:37 ` Kirill A. Shutemov
2023-05-30 12:09 ` [patch] x86/smpboot: Disable parallel bootup if cc_vendor != NONE Thomas Gleixner
2023-05-30 12:29 ` Kirill A. Shutemov
2023-05-30 16:00 ` Thomas Gleixner
2023-05-30 16:56 ` Sean Christopherson
2023-05-30 19:51 ` Thomas Gleixner
2023-05-30 20:03 ` Tom Lendacky [this message]
2023-05-30 20:39 ` Thomas Gleixner
2023-05-30 21:13 ` Tom Lendacky
2023-05-31 7:44 ` [patch] x86/smpboot: Fix the parallel bringup decision Thomas Gleixner
2023-05-31 11:07 ` Kirill A. Shutemov
2023-05-31 13:58 ` Tom Lendacky
2023-05-30 17:02 ` [patch] x86/smpboot: Disable parallel bootup if cc_vendor != NONE Kirill A. Shutemov
2023-05-30 17:31 ` Sean Christopherson
2023-05-30 9:26 ` [patch v3 31/36] x86/apic: Provide cpu_primary_thread mask Thomas Gleixner
2023-05-30 10:46 ` [patch] x86/realmode: Make stack lock work in trampoline_compat() Thomas Gleixner
2023-05-30 11:12 ` Kirill A. Shutemov
2023-06-08 23:34 ` Yunhong Jiang
2023-06-08 23:57 ` Andrew Cooper
2023-06-09 0:22 ` Yunhong Jiang
2023-06-10 19:50 ` David Laight
2023-06-10 22:51 ` 'Andrew Cooper'
2023-05-08 19:44 ` [patch v3 32/36] cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE Thomas Gleixner
2023-05-08 19:44 ` [patch v3 33/36] x86/apic: Save the APIC virtual base address Thomas Gleixner
2023-05-09 9:20 ` Sergey Shtylyov
2023-05-08 19:44 ` [patch v3 34/36] x86/smpboot: Implement a bit spinlock to protect the realmode stack Thomas Gleixner
2023-05-09 13:13 ` Peter Zijlstra
2023-05-09 13:47 ` Thomas Gleixner
2023-05-08 19:44 ` [patch v3 35/36] x86/smpboot: Support parallel startup of secondary CPUs Thomas Gleixner
2023-05-09 13:57 ` Peter Zijlstra
2023-05-08 19:44 ` [patch v3 36/36] x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it Thomas Gleixner
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