From: Avi Kivity <avi@redhat.com> To: "H. Peter Anvin" <hpa@zytor.com> Cc: Gleb Natapov <gleb@redhat.com>, Peter Zijlstra <peterz@infradead.org>, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, riel@redhat.com, cl@linux-foundation.org Subject: Re: [PATCH v3 04/12] Add "handle page fault" PV helper. Date: Thu, 21 Jan 2010 11:02:19 +0200 [thread overview] Message-ID: <4B58181B.60405@redhat.com> (raw) In-Reply-To: <4B5740CD.4020005@zytor.com> On 01/20/2010 07:43 PM, H. Peter Anvin wrote: > On 01/20/2010 02:02 AM, Gleb Natapov wrote: >> >>> You can have the guest OS take an exception on a vector above 31 just >>> fine; you just need it to tell the hypervisor which vector it, the OS, >>> assigned for this purpose. >>> >> VMX doesn't allow to inject hardware exception with vector greater >> then 31. >> SDM 3B section 23.2.1.3. >> > > OK, you're right. I had missed that... I presume it was done for > implementation reasons. My expectation is that is was done for forward compatibility reasons. > >> I can inject the event as HW interrupt on vector greater then 32 but not >> go through APIC so EOI will not be required. This sounds >> non-architectural >> and I am not sure kernel has entry point code for this kind of event, it >> has one for exception and one for interrupts that goes through >> __do_IRQ() >> which assumes that interrupts should be ACKed. > > You can also just emulate the state transition -- since you know > you're dealing with a flat protected-mode or long-mode OS (and just > make that a condition of enabling the feature) you don't have to deal > with all the strange combinations of directions that an unrestricted > x86 event can take. Since it's an exception, it is unconditional. Do you mean create the stack frame manually? I'd really like to avoid that for many reasons, one of which is performance (need to do all the virt-to-phys walks manually), the other is that we're certain to end up with something horribly underspecified. I'd really like to keep as close as possible to the hardware. For the alternative approach, see Xen. -- error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com> To: "H. Peter Anvin" <hpa@zytor.com> Cc: Gleb Natapov <gleb@redhat.com>, Peter Zijlstra <peterz@infradead.org>, kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, riel@redhat.com, cl@linux-foundation.org Subject: Re: [PATCH v3 04/12] Add "handle page fault" PV helper. Date: Thu, 21 Jan 2010 11:02:19 +0200 [thread overview] Message-ID: <4B58181B.60405@redhat.com> (raw) In-Reply-To: <4B5740CD.4020005@zytor.com> On 01/20/2010 07:43 PM, H. Peter Anvin wrote: > On 01/20/2010 02:02 AM, Gleb Natapov wrote: >> >>> You can have the guest OS take an exception on a vector above 31 just >>> fine; you just need it to tell the hypervisor which vector it, the OS, >>> assigned for this purpose. >>> >> VMX doesn't allow to inject hardware exception with vector greater >> then 31. >> SDM 3B section 23.2.1.3. >> > > OK, you're right. I had missed that... I presume it was done for > implementation reasons. My expectation is that is was done for forward compatibility reasons. > >> I can inject the event as HW interrupt on vector greater then 32 but not >> go through APIC so EOI will not be required. This sounds >> non-architectural >> and I am not sure kernel has entry point code for this kind of event, it >> has one for exception and one for interrupts that goes through >> __do_IRQ() >> which assumes that interrupts should be ACKed. > > You can also just emulate the state transition -- since you know > you're dealing with a flat protected-mode or long-mode OS (and just > make that a condition of enabling the feature) you don't have to deal > with all the strange combinations of directions that an unrestricted > x86 event can take. Since it's an exception, it is unconditional. Do you mean create the stack frame manually? I'd really like to avoid that for many reasons, one of which is performance (need to do all the virt-to-phys walks manually), the other is that we're certain to end up with something horribly underspecified. I'd really like to keep as close as possible to the hardware. For the alternative approach, see Xen. -- error compiling committee.c: too many arguments to function -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-01-21 9:03 UTC|newest] Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-01-05 14:12 [PATCH v3 00/12] KVM: Add host swap event notifications for PV guest Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 01/12] Move kvm_smp_prepare_boot_cpu() from kvmclock.c to kvm.c Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 02/12] Add PV MSR to enable asynchronous page faults delivery Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-06 9:57 ` [Qemu-devel] Fw: " Dor Laor 2010-01-06 10:04 ` [Qemu-devel] " Gleb Natapov 2010-01-06 10:28 ` Gerd Hoffmann 2010-01-06 13:20 ` Anthony Liguori 2010-01-05 14:12 ` [PATCH v3 03/12] Add async PF initialization to PV guest Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 04/12] Add "handle page fault" PV helper Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-14 17:31 ` Peter Zijlstra 2010-01-14 17:31 ` Peter Zijlstra 2010-01-14 17:31 ` Peter Zijlstra 2010-01-17 14:44 ` Gleb Natapov 2010-01-17 14:44 ` Gleb Natapov 2010-01-17 15:09 ` Peter Zijlstra 2010-01-17 15:09 ` Peter Zijlstra 2010-01-17 15:09 ` Peter Zijlstra 2010-01-17 15:12 ` Gleb Natapov 2010-01-17 15:12 ` Gleb Natapov 2010-01-18 9:53 ` Andi Kleen 2010-01-18 9:53 ` Andi Kleen 2010-01-18 9:53 ` Andi Kleen 2010-01-18 8:34 ` H. Peter Anvin 2010-01-18 8:34 ` H. Peter Anvin 2010-01-18 8:50 ` Gleb Natapov 2010-01-18 8:50 ` Gleb Natapov 2010-01-19 1:53 ` H. Peter Anvin 2010-01-19 1:53 ` H. Peter Anvin 2010-01-19 6:55 ` Gleb Natapov 2010-01-19 6:55 ` Gleb Natapov 2010-01-19 17:03 ` H. Peter Anvin 2010-01-19 17:03 ` H. Peter Anvin 2010-01-19 17:44 ` Gleb Natapov 2010-01-19 17:44 ` Gleb Natapov 2010-01-19 20:10 ` H. Peter Anvin 2010-01-19 20:10 ` H. Peter Anvin 2010-01-20 10:02 ` Gleb Natapov 2010-01-20 10:02 ` Gleb Natapov 2010-01-20 12:00 ` Avi Kivity 2010-01-20 12:00 ` Avi Kivity 2010-01-20 17:18 ` Rik van Riel 2010-01-20 17:18 ` Rik van Riel 2010-01-21 8:56 ` Avi Kivity 2010-01-21 8:56 ` Avi Kivity 2010-01-20 18:45 ` H. Peter Anvin 2010-01-20 18:45 ` H. Peter Anvin 2010-01-21 8:58 ` Avi Kivity 2010-01-21 8:58 ` Avi Kivity 2010-01-20 17:43 ` H. Peter Anvin 2010-01-20 17:43 ` H. Peter Anvin 2010-01-21 9:02 ` Avi Kivity [this message] 2010-01-21 9:02 ` Avi Kivity 2010-01-21 9:04 ` Gleb Natapov 2010-01-21 9:04 ` Gleb Natapov 2010-01-21 9:05 ` Avi Kivity 2010-01-21 9:05 ` Avi Kivity 2010-01-21 15:47 ` H. Peter Anvin 2010-01-21 15:47 ` H. Peter Anvin 2010-01-22 7:25 ` Gleb Natapov 2010-01-22 7:25 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 05/12] Export __get_user_pages_fast Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-17 15:46 ` Christoph Hellwig 2010-01-17 15:46 ` Christoph Hellwig 2010-01-05 14:12 ` [PATCH v3 06/12] Add get_user_pages() variant that fails if major fault is required Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-17 15:43 ` Christoph Hellwig 2010-01-17 15:43 ` Christoph Hellwig 2010-01-05 14:12 ` [PATCH v3 07/12] Maintain memslot version number Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 08/12] Inject asynchronous page fault into a guest if page is swapped out Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 09/12] Retry fault before vmentry Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 10/12] Handle async PF in non preemptable context Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 11/12] Let host know whether the guest can handle async PF in non-userspace context Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 14:12 ` [PATCH v3 12/12] Send async PF when guest is not in userspace too Gleb Natapov 2010-01-05 14:12 ` Gleb Natapov 2010-01-05 15:05 ` [PATCH v3 00/12] KVM: Add host swap event notifications for PV guest Jun Koi 2010-01-05 15:05 ` Jun Koi 2010-01-05 15:59 ` Rik van Riel 2010-01-05 15:59 ` Rik van Riel 2010-01-05 16:04 ` Avi Kivity 2010-01-05 16:04 ` Avi Kivity 2010-01-06 10:17 ` Jun Koi 2010-01-06 10:17 ` Jun Koi 2010-01-06 10:21 ` Gleb Natapov 2010-01-06 10:21 ` Gleb Natapov 2010-01-08 16:18 ` Marcelo Tosatti 2010-01-08 16:18 ` Marcelo Tosatti 2010-01-08 16:47 ` Gleb Natapov 2010-01-08 16:47 ` Gleb Natapov 2010-01-08 19:24 ` Rik van Riel 2010-01-08 19:24 ` Rik van Riel 2010-01-08 19:30 ` Bryan Donlan 2010-01-08 19:30 ` Bryan Donlan 2010-01-08 19:55 ` Rik van Riel 2010-01-08 19:55 ` Rik van Riel
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