Messages in this thread | | | Subject | Re: [PATCH v2 3/6] KVM: x86: make pic setup code look like ioapic setup | From | David Hildenbrand <> | Date | Wed, 4 Jan 2017 10:10:40 +0100 |
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Am 03.01.2017 um 17:12 schrieb Paolo Bonzini: > > > On 03/01/2017 14:04, David Hildenbrand wrote: >> Am 16.12.2016 um 16:10 schrieb Radim Krčmář: >>> We don't treat kvm->arch.vpic specially anymore, so the setup can look >>> like ioapic. This gets a bit more information out of return values. >> >> This originally saved us from a race condition as far as I can >> reconstruct from the commit history. Think the problem was >> vpic being set but routes not being set up yet. >> >> commit 71ba994c94a81c37185ef2fb5190844286ba9aca >> Author: Paolo Bonzini <pbonzini@redhat.com> >> Date: Wed Jul 29 12:31:15 2015 +0200 >> >> KVM: x86: clean/fix memory barriers in irqchip_in_kernel >> >> The memory barriers are trying to protect against concurrent RCU-based >> interrupt injection, but the IRQ routing table is not valid at the time >> kvm->arch.vpic is written. Fix this by writing kvm->arch.vpic last. >> kvm_destroy_pic then need not set kvm->arch.vpic to NULL; modify it >> to take a struct kvm_pic* and reuse it if the IOAPIC creation fails. >> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >> >> I assume that this is now fixed via the irqchip_mode, as it is stored >> last? If so, I really like this patch :) > > Yes, the previous patch referred to that when it said > "irqchip_in_kernel() tried to save a bit by reusing pic_irqchip()", and > what this commit message means by "not trteating kvm->arch.vpic > specially anymore".
Thanks for confirming!
Reviewed-by: David Hildenbrand <david@redhat.com>
> > Paolo >
--
David
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