From: Gleb Natapov <gleb@redhat.com> To: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org>, Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>, KVM <kvm@vger.kernel.org>, linux-doc@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, Jan Kiszka <jan.kiszka@siemens.com>, Virtualization <virtualization@lists.linux-foundation.org>, Paul Mackerras <paulus@samba.org>, "H. Peter Anvin" <hpa@zytor.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Xen <xen-devel@lists.xensource.com>, Dave Jiang <dave.jiang@intel.com>, Glauber Costa <glommer@redhat.com>, X86 <x86@kernel.org>, Ingo Molnar <mingo@redhat.com>, Avi Kivity <avi@redhat.com>, Rik van Riel <riel@redhat.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Sasha Levin <levinsasha928@gmail.com>, Sedat Dilek <sedat.dilek@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Greg Kroah-Hartman <gregkh@suse.de>, LKML <linux-kernel@vger.kernel.org>, Dave Hansen <dave Subject: Re: [PATCH RFC V4 5/5] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock Date: Tue, 17 Jan 2012 14:51:26 +0200 [thread overview] Message-ID: <20120117125126.GQ2167@redhat.com> (raw) In-Reply-To: <20120117122650.GC30757@linux.vnet.ibm.com> On Tue, Jan 17, 2012 at 05:56:50PM +0530, Srivatsa Vaddagiri wrote: > * Gleb Natapov <gleb@redhat.com> [2012-01-17 11:14:13]: > > > > The problem case I was thinking of was when guest VCPU would have issued > > > HLT with interrupts disabled. I guess one option is to inject an NMI, > > > and have the guest kernel NMI handler recognize this and make > > > adjustments such that the vcpu avoids going back to HLT instruction. > > > > > Just kick vcpu out of a guest mode and adjust rip to point after HLT on > > next re-entry. Don't forget to call vmx_clear_hlt(). > > Looks bit hackish to me compared to having another hypercall to yield! > Do not see anything hackish about it. But what you described above (the part I replied to) is not another hypercall, but yet another NMI source and special handling in a guest. So what hypercall do you mean? > > > Having another hypercall to do yield/sleep (rather than effecting that > > > via HLT) seems like an alternate clean solution here .. > > - vatsa -- Gleb.
WARNING: multiple messages have this Message-ID (diff)
From: Gleb Natapov <gleb@redhat.com> To: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org>, Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>, KVM <kvm@vger.kernel.org>, linux-doc@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, Jan Kiszka <jan.kiszka@siemens.com>, Virtualization <virtualization@lists.linux-foundation.org>, Paul Mackerras <paulus@samba.org>, "H. Peter Anvin" <hpa@zytor.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Xen <xen-devel@lists.xensource.com>, Dave Jiang <dave.jiang@intel.com>, Glauber Costa <glommer@redhat.com>, X86 <x86@kernel.org>, Ingo Molnar <mingo@redhat.com>, Avi Kivity <avi@redhat.com>, Rik van Riel <riel@redhat.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Sasha Levin <levinsasha928@gmail.com>, Sedat Dilek <sedat.dilek@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Greg Kroah-Hartman <gregkh@suse.de>, LKML <linux-kernel@vger.kernel.org>Dave Hansen <dave> Subject: Re: [PATCH RFC V4 5/5] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock Date: Tue, 17 Jan 2012 14:51:26 +0200 [thread overview] Message-ID: <20120117125126.GQ2167@redhat.com> (raw) In-Reply-To: <20120117122650.GC30757@linux.vnet.ibm.com> On Tue, Jan 17, 2012 at 05:56:50PM +0530, Srivatsa Vaddagiri wrote: > * Gleb Natapov <gleb@redhat.com> [2012-01-17 11:14:13]: > > > > The problem case I was thinking of was when guest VCPU would have issued > > > HLT with interrupts disabled. I guess one option is to inject an NMI, > > > and have the guest kernel NMI handler recognize this and make > > > adjustments such that the vcpu avoids going back to HLT instruction. > > > > > Just kick vcpu out of a guest mode and adjust rip to point after HLT on > > next re-entry. Don't forget to call vmx_clear_hlt(). > > Looks bit hackish to me compared to having another hypercall to yield! > Do not see anything hackish about it. But what you described above (the part I replied to) is not another hypercall, but yet another NMI source and special handling in a guest. So what hypercall do you mean? > > > Having another hypercall to do yield/sleep (rather than effecting that > > > via HLT) seems like an alternate clean solution here .. > > - vatsa -- Gleb.
next prev parent reply other threads:[~2012-01-17 12:51 UTC|newest] Thread overview: 139+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-01-14 18:25 [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Raghavendra K T 2012-01-14 18:25 ` Raghavendra K T 2012-01-14 18:25 ` Raghavendra K T 2012-01-14 18:25 ` [PATCH RFC V4 1/5] debugfs: Add support to print u32 array in debugfs Raghavendra K T 2012-01-14 18:25 ` Raghavendra K T 2012-01-14 18:25 ` Raghavendra K T 2012-01-14 18:25 ` [PATCH RFC V4 2/5] kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks Raghavendra K T 2012-01-14 18:25 ` Raghavendra K T 2012-01-14 18:25 ` Raghavendra K T 2012-01-16 3:24 ` Alexander Graf 2012-01-16 3:24 ` Alexander Graf 2012-01-16 8:43 ` Raghavendra K T 2012-01-16 8:43 ` Raghavendra K T 2012-01-16 9:03 ` Avi Kivity 2012-01-16 9:03 ` Avi Kivity 2012-01-16 9:55 ` Raghavendra K T 2012-01-16 9:55 ` Raghavendra K T 2012-01-14 18:26 ` [PATCH RFC V4 3/5] kvm guest : Added configuration support to enable debug information for KVM Guests Raghavendra K T 2012-01-14 18:26 ` Raghavendra K T 2012-01-14 18:26 ` Raghavendra K T 2012-01-14 18:26 ` [PATCH RFC V4 4/5] kvm : pv-ticketlocks support for linux guests running on KVM hypervisor Raghavendra K T 2012-01-14 18:26 ` Raghavendra K T 2012-01-14 18:26 ` Raghavendra K T 2012-01-16 3:12 ` Alexander Graf 2012-01-16 3:12 ` Alexander Graf 2012-01-16 7:25 ` Raghavendra K T 2012-01-16 7:25 ` Raghavendra K T 2012-01-16 9:05 ` Avi Kivity 2012-01-16 9:05 ` Avi Kivity 2012-01-16 14:13 ` Raghavendra K T 2012-01-16 14:13 ` Raghavendra K T 2012-01-16 14:47 ` Avi Kivity 2012-01-16 14:47 ` Avi Kivity 2012-01-16 23:49 ` Jeremy Fitzhardinge 2012-01-16 23:49 ` Jeremy Fitzhardinge 2012-01-17 11:02 ` Marcelo Tosatti 2012-01-17 11:02 ` Marcelo Tosatti 2012-01-17 11:33 ` Srivatsa Vaddagiri 2012-01-17 11:33 ` Srivatsa Vaddagiri 2012-01-18 1:34 ` Jeremy Fitzhardinge 2012-01-18 1:34 ` Jeremy Fitzhardinge 2012-01-18 13:54 ` Srivatsa Vaddagiri 2012-01-18 13:54 ` Srivatsa Vaddagiri 2012-01-18 21:52 ` Jeremy Fitzhardinge 2012-01-18 21:52 ` Jeremy Fitzhardinge 2012-01-24 14:08 ` Avi Kivity 2012-01-24 14:08 ` Avi Kivity 2012-01-24 18:51 ` Raghavendra K T 2012-01-24 18:51 ` Raghavendra K T 2012-01-17 18:57 ` Raghavendra K T 2012-01-17 18:57 ` Raghavendra K T 2012-01-24 19:01 ` Raghavendra K T 2012-01-14 18:27 ` [PATCH RFC V4 5/5] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock Raghavendra K T 2012-01-14 18:27 ` Raghavendra K T 2012-01-14 18:27 ` Raghavendra K T 2012-01-14 18:27 ` Raghavendra K T 2012-01-16 3:23 ` Alexander Graf 2012-01-16 3:23 ` Alexander Graf 2012-01-16 3:51 ` Srivatsa Vaddagiri 2012-01-16 3:51 ` Srivatsa Vaddagiri 2012-01-16 4:00 ` Alexander Graf 2012-01-16 4:00 ` Alexander Graf 2012-01-16 8:47 ` Avi Kivity 2012-01-16 8:44 ` Raghavendra K T 2012-01-16 8:44 ` Raghavendra K T 2012-01-16 10:26 ` Alexander Graf 2012-01-16 10:26 ` Alexander Graf 2012-01-16 9:00 ` Avi Kivity 2012-01-16 9:00 ` Avi Kivity 2012-01-16 9:40 ` Srivatsa Vaddagiri 2012-01-16 10:14 ` Avi Kivity 2012-01-16 14:11 ` Srivatsa Vaddagiri 2012-01-17 9:14 ` Gleb Natapov 2012-01-17 9:14 ` Gleb Natapov 2012-01-17 12:26 ` Srivatsa Vaddagiri 2012-01-17 12:26 ` Srivatsa Vaddagiri 2012-01-17 12:51 ` Gleb Natapov [this message] 2012-01-17 12:51 ` Gleb Natapov 2012-01-17 13:11 ` Srivatsa Vaddagiri 2012-01-17 13:11 ` Srivatsa Vaddagiri 2012-01-17 13:20 ` Gleb Natapov 2012-01-17 13:20 ` Gleb Natapov 2012-01-17 14:28 ` Srivatsa Vaddagiri 2012-01-17 14:28 ` Srivatsa Vaddagiri 2012-01-17 15:32 ` Gleb Natapov 2012-01-17 15:32 ` Gleb Natapov 2012-01-17 15:53 ` Marcelo Tosatti 2012-01-17 15:53 ` Marcelo Tosatti 2012-01-20 15:09 ` Srivatsa Vaddagiri 2012-01-17 13:13 ` Raghavendra K T 2012-01-17 13:13 ` Raghavendra K T 2012-01-16 3:57 ` [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Alexander Graf 2012-01-16 3:57 ` Alexander Graf 2012-01-16 6:40 ` Jeremy Fitzhardinge 2012-01-16 6:40 ` Jeremy Fitzhardinge 2012-01-16 8:55 ` Avi Kivity 2012-01-16 8:55 ` Avi Kivity 2012-01-16 23:59 ` Jeremy Fitzhardinge 2012-01-16 23:59 ` Jeremy Fitzhardinge 2012-01-18 10:48 ` Raghavendra K T 2012-01-18 10:48 ` Raghavendra K T 2012-01-16 10:24 ` Alexander Graf 2012-01-16 10:24 ` Alexander Graf 2012-01-17 0:30 ` Jeremy Fitzhardinge 2012-01-17 0:30 ` Jeremy Fitzhardinge 2012-01-18 10:23 ` Raghavendra K T 2012-01-18 10:23 ` Raghavendra K T 2012-01-16 13:43 ` Raghavendra K T 2012-01-16 13:43 ` Raghavendra K T 2012-01-16 13:49 ` Avi Kivity 2012-01-16 13:49 ` Avi Kivity 2012-01-16 18:48 ` Raghavendra K T 2012-01-16 18:48 ` Raghavendra K T 2012-01-16 14:20 ` Srivatsa Vaddagiri 2012-01-16 14:20 ` Srivatsa Vaddagiri 2012-01-16 14:23 ` Alexander Graf 2012-01-16 14:23 ` Alexander Graf 2012-01-16 18:38 ` Raghavendra K T 2012-01-16 18:38 ` Raghavendra K T 2012-01-16 18:42 ` Alexander Graf 2012-01-16 18:42 ` Alexander Graf 2012-01-17 17:27 ` Raghavendra K T 2012-01-17 17:27 ` Raghavendra K T 2012-01-17 17:39 ` Alexander Graf 2012-01-17 17:39 ` Alexander Graf 2012-01-17 18:36 ` Raghavendra K T 2012-01-17 18:36 ` Raghavendra K T 2012-01-17 21:57 ` Dave Hansen 2012-01-17 21:57 ` Dave Hansen 2012-01-18 2:27 ` Raghavendra K T 2012-01-18 2:27 ` Raghavendra K T 2012-01-25 8:55 ` Raghavendra K T 2012-01-25 8:55 ` Raghavendra K T 2012-01-25 16:35 ` Konrad Rzeszutek Wilk 2012-01-25 16:35 ` Konrad Rzeszutek Wilk 2012-01-25 17:45 ` Raghavendra K T 2012-01-25 17:45 ` Raghavendra K T 2012-01-25 19:05 ` Konrad Rzeszutek Wilk 2012-01-25 19:05 ` Konrad Rzeszutek Wilk
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