Messages in this thread Patches in this message | | | Date | Fri, 05 Jan 2007 14:15:19 -0800 | From | Zachary Amsden <> | Subject | Re: [announce] [patch] KVM paravirtualization for Linux |
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Ingo Molnar wrote: > i'm pleased to announce the first release of paravirtualized KVM (Linux > under Linux), which includes support for the hardware cr3-cache feature > of Intel-VMX CPUs. (which speeds up context switches and TLB flushes) > > the patch is against 2.6.20-rc3 + KVM trunk and can be found at: > > http://redhat.com/~mingo/kvm-paravirt-patches/ > > Some aspects of the code are still a bit ad-hoc and incomplete, but the > code is stable enough in my testing and i'd like to have some feedback. >
Your code looks generally good. I have some comments.
You can't do this, even though you want to:
-EXPORT_SYMBOL(paravirt_ops); +EXPORT_SYMBOL_GPL(paravirt_ops);
The problem is it makes all modules GPL - or at least all modules that use any kind of locking, pull in the basic definitions to enable and disable interrupts, thus the paravirt_ops symbol, so basically all modules.
What you really want is more like EXPORT_SYMBOL_READABLE_GPL(paravirt_ops);
But I'm not sure that is technically feasible yet.
The kvm code should probably go in kvm.c instead of paravirt.c.
Index: linux/drivers/serial/8250.c =================================================================== --- linux.orig/drivers/serial/8250.c +++ linux/drivers/serial/8250.c @@ -1371,7 +1371,7 @@ static irqreturn_t serial8250_interrupt( l = l->next; - if (l == i->head && pass_counter++ > PASS_LIMIT) { + if (!kvm_paravirt
Is this a bug that might happen under other virtualizations as well, not just kvm? Perhaps it deserves a disable feature instead of a kvm specific check. Which also gets rid of the need for this unusually placed extern:
Index: linux/include/linux/sched.h =================================================================== --- linux.orig/include/linux/sched.h +++ linux/include/linux/sched.h @@ -1911,6 +1911,11 @@ static inline void set_task_cpu(struct t #endif /* CONFIG_SMP */ +/* + * Is paravirtualization active? + */ +extern int kvm_paravirt;
+
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