From: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
David Hildenbrand <david@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
Tony Luck <tony.luck@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Sean Christopherson <seanjc@google.com>,
Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 3/6] x86/topology: Disable CPU online/offline control for TDX guest
Date: Sun, 17 Oct 2021 12:28:39 -0700 [thread overview]
Message-ID: <8eef611f-77e1-aec5-3e1f-24a14ad50c91@linux.intel.com> (raw)
In-Reply-To: <877deb4frg.ffs@tglx>
On 10/17/21 12:23 PM, Thomas Gleixner wrote:
> Seriously? This lets the unplug start, which starts to kick off tasks
> from the CPU just to make it fail a few steps later?
>
> The obvious place to prevent this is the CPU hotplug code itself, right?
>
> Thanks,
>
> tglx
> ---
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 192e43a87407..c544eb6c79d3 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -1178,6 +1178,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
>
> static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target)
> {
> + if (cc_platform_has(CC_HOTPLUG_DISABLED))
> + return -ENOTSUPP;
> if (cpu_hotplug_disabled)
> return -EBUSY;
> return _cpu_down(cpu, 0, target);
Makes sense. I will use it in next version.
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
next prev parent reply other threads:[~2021-10-17 19:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 23:05 [PATCH v7 0/6] Add TDX Guest Support (boot support) Kuppuswamy Sathyanarayanan
2021-10-05 23:05 ` [PATCH v7 1/6] x86/boot: Add a trampoline for APs booting in 64-bit mode Kuppuswamy Sathyanarayanan
2021-10-05 23:05 ` [PATCH v7 2/6] x86/boot: Avoid #VE during boot for TDX platforms Kuppuswamy Sathyanarayanan
2021-10-17 19:49 ` Thomas Gleixner
2021-10-05 23:05 ` [PATCH v7 3/6] x86/topology: Disable CPU online/offline control for TDX guest Kuppuswamy Sathyanarayanan
2021-10-17 19:23 ` Thomas Gleixner
2021-10-17 19:28 ` Sathyanarayanan Kuppuswamy [this message]
2021-10-05 23:05 ` [PATCH v7 4/6] x86/tdx: Forcefully disable legacy PIC for TDX guests Kuppuswamy Sathyanarayanan
2021-10-05 23:05 ` [PATCH v7 5/6] x86: Skip WBINVD instruction for VM guest Kuppuswamy Sathyanarayanan
2021-10-05 23:05 ` [PATCH v7 6/6] x86/split_lock: Fix the split lock #AC handling when running as guest Kuppuswamy Sathyanarayanan
2021-10-13 20:30 ` Sean Christopherson
2021-10-13 21:32 ` Sathyanarayanan Kuppuswamy
2021-10-14 1:24 ` Xiaoyao Li
2021-10-14 2:21 ` Sathyanarayanan Kuppuswamy
2021-10-14 15:04 ` Sean Christopherson
2021-10-15 1:30 ` Xiaoyao Li
2021-10-06 8:21 ` [PATCH v7 0/6] Add TDX Guest Support (boot support) David Hildenbrand
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