[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap paramet
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state |
Date: |
Thu, 24 Jan 2013 19:26:17 +0100 |
On 24.01.2013, at 19:17, Scott Wood wrote:
> On 01/24/2013 06:41:05 AM, Alexander Graf wrote:
>> On 16.01.2013, at 18:23, Marcelo Tosatti wrote:
>> > What register is that and why it cannot be synced normally? When is it
>> > necessary to sync it?
>> We need to sync it on the above 2 occasions.
>> Thinking about this a bit more, we're trying to keep the synchronization
>> window short to not get into conflicts with the kernel timer kicking in in
>> between. Imagine this race:
>> * user space reads TSR
>> * kernel timer expires, sets bit in TSR
>> * user space writes TSR
>> That's why we don't want this to be synced every time. We would only set TSR
>> when we reset the counter. At that point in time it doesn't hurt to lose the
>> kernel timer set, because we cleared the bit anyways.
>> But maybe the better solution would be a special "write to clear" ONE_REG
>> register to clear specific bits and a big hammer "set" ONE_REG (which we
>> have already) for reset only.
>> That would make things easier, right? Scott, any ideas on this?
>
> Yes, we should have a ONE_REG write-to-clear TSR. Maybe a write-to-set
> version as well, in case userspace wants to inject something. Likewise for
> MCSR.
Bharat, could you please quickly write up a patch to do this?
Thanks!
Alex
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, (continued)
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Blue Swirl, 2013/01/12
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Bhushan Bharat-R65777, 2013/01/14
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Bhushan Bharat-R65777, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Alexander Graf, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Scott Wood, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Peter Maydell, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Alexander Graf, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Scott Wood, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state,
Alexander Graf <=
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/16
Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/16
Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Christian Borntraeger, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Christian Borntraeger, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/16
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Alexander Graf, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Marcelo Tosatti, 2013/01/24
- Re: [Qemu-devel] [PATCH 4/7 v2] KVM regsync: Add register bitmap parameter to do_kvm_cpu_synchronize_state, Alexander Graf, 2013/01/24