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 11:14:13 +0200 [thread overview]
Message-ID: <20120117091413.GM2167@redhat.com> (raw)
In-Reply-To: <20120116141117.GB6019@linux.vnet.ibm.com>
On Mon, Jan 16, 2012 at 07:41:17PM +0530, Srivatsa Vaddagiri wrote:
> * Avi Kivity <avi@redhat.com> [2012-01-16 12:14:27]:
>
> > > One option is to make the kick hypercall available only when
> > > yield_on_hlt=1?
> >
> > It's not a good idea to tie various options together. Features should
> > be orthogonal.
> >
> > Can't we make it work? Just have different handling for
> > KVM_REQ_PVLOCK_KICK (let 's rename it, and the hypercall, PV_UNHALT,
> > since we can use it for non-locks too).
>
> 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().
> 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 9:14 UTC|newest]
Thread overview: 69+ 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 ` [PATCH RFC V4 1/5] debugfs: Add support to print u32 array in debugfs 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
2012-01-16 3:24 ` Alexander Graf
2012-01-16 8:43 ` Raghavendra K T
2012-01-16 9:03 ` Avi Kivity
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 ` [PATCH RFC V4 4/5] kvm : pv-ticketlocks support for linux guests running on KVM hypervisor Raghavendra K T
2012-01-16 3:12 ` Alexander Graf
2012-01-16 7:25 ` Raghavendra K T
2012-01-16 9:05 ` Avi Kivity
2012-01-16 14:13 ` Raghavendra K T
2012-01-16 14:47 ` Avi Kivity
2012-01-16 23:49 ` Jeremy Fitzhardinge
2012-01-17 11:02 ` Marcelo Tosatti
2012-01-17 11:33 ` Srivatsa Vaddagiri
2012-01-18 1:34 ` Jeremy Fitzhardinge
2012-01-18 13:54 ` Srivatsa Vaddagiri
2012-01-18 21:52 ` Jeremy Fitzhardinge
2012-01-24 14:08 ` Avi Kivity
2012-01-24 18:51 ` 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
2012-01-16 3:57 ` [PATCH RFC V4 0/5] kvm : Paravirt-spinlock support for KVM guests Alexander Graf
2012-01-16 6:40 ` Jeremy Fitzhardinge
2012-01-16 8:55 ` Avi Kivity
2012-01-16 23:59 ` Jeremy Fitzhardinge
2012-01-18 10:48 ` Raghavendra K T
2012-01-16 10:24 ` Alexander Graf
2012-01-17 0:30 ` Jeremy Fitzhardinge
2012-01-18 10:23 ` Raghavendra K T
2012-01-16 13:43 ` Raghavendra K T
2012-01-16 13:49 ` Avi Kivity
2012-01-16 18:48 ` Raghavendra K T
2012-01-16 14:20 ` Srivatsa Vaddagiri
2012-01-16 14:23 ` Alexander Graf
2012-01-16 18:38 ` Raghavendra K T
2012-01-16 18:42 ` Alexander Graf
2012-01-17 17:27 ` Raghavendra K T
2012-01-17 17:39 ` Alexander Graf
2012-01-17 18:36 ` Raghavendra K T
2012-01-17 21:57 ` Dave Hansen
2012-01-18 2:27 ` Raghavendra K T
2012-01-25 8:55 ` Raghavendra K T
2012-01-25 16:35 ` Konrad Rzeszutek Wilk
2012-01-25 17:45 ` Raghavendra K T
2012-01-25 19:05 ` Konrad Rzeszutek Wilk
[not found] ` <20120114182710.8604.22277.sendpatchset@oc5400248562.ibm.com>
2012-01-16 3:23 ` [PATCH RFC V4 5/5] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock Alexander Graf
2012-01-16 3:51 ` Srivatsa Vaddagiri
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 10:26 ` Alexander Graf
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 [this message]
2012-01-17 12:26 ` Srivatsa Vaddagiri
2012-01-17 12:51 ` Gleb Natapov
2012-01-17 13:11 ` Srivatsa Vaddagiri
2012-01-17 13:20 ` Gleb Natapov
2012-01-17 14:28 ` Srivatsa Vaddagiri
2012-01-17 15:32 ` Gleb Natapov
2012-01-17 15:53 ` Marcelo Tosatti
2012-01-20 15:09 ` Srivatsa Vaddagiri
2012-01-17 13:13 ` Raghavendra K T
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