Messages in this thread | | | Date | Wed, 28 Oct 2020 09:54:05 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86: Drop RDPID macro to discourage use of RDPID in the kernel |
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On Tue, Oct 27, 2020 at 02:45:32PM -0700, Sean Christopherson wrote: > Drop the GAS-compatible RDPID macro as RDPID shouldn't be used in the > kernel, excepting the vDSO, which handcodes RDPID in inline asm. RDPID > is unsafe in the kernel because KVM loads guest's TSC_AUX on VM-entry > and may not restore the host's value until the CPU returns to userspace. > > See commit 6a3ea3e68b8a ("x86/entry/64: Do not use RDPID in paranoid > entry to accomodate KVM") for details.
Well, remove it because there is no (current) user, OK. But if there's a compelling kernel side use for it, KVM can go suck rocks.
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