Re: [XenPPC] fast_resume instead of full_resume after hdec_out
Sounds reasonable to me. When I get a chance I'll try it out; I need to do a little work to track upstream Xen changes anyways. I don't think I'll have time in the next two weeks though (just FYI)... On Tue, 2007-09-11 at 04:22 +, HYEONSEUNG JANG wrote: In handling hdec exception, non-volatile registers are saved because context_switch() may be called in the do_softirq(). The fact that we reach to 'hdec_out' means that there has been no context_switch() called. But currently 'fast_resume' is called after 'hdec_out' I think there seems to be no reason to restore non-volatiles at this point. Becasue MSR_EE is alwyas 0, 'fast_resume' will be enough like the following. It seems to work well in our HW. Please give me comments or something. - Hyeonseung Jang. diff -r 9071521d4864 xen/arch/powerpc/powerpc64/exceptions.S --- a/xen/arch/powerpc/powerpc64/exceptions.S Fri Sep 07 11:39:10 2007 +0100 +++ b/xen/arch/powerpc/powerpc64/exceptions.S Tue Sep 11 11:38:25 2007 +0900 @@ -514,6 +514,7 @@ hdec_out: hdec_out: addi r1, r1, STACK_FRAME_OVERHEAD /* restore stack to cpu_user_regs */ LOAD_GPRS r14, r15, r1 /* we clobbered r14/r15 in the loop */ +b fast_resume /* r1 points to the to-be-restored cpu_user_regs. These could be mid-hypervisor * stack (returning into elsewhere in Xen) or at the top of the stack ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel -- Hollis Blanchard IBM Linux Technology Center ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
[XenPPC] fast_resume instead of full_resume after hdec_out
In handling hdec exception, non-volatile registers are saved because context_switch() may be called in the do_softirq(). The fact that we reach to 'hdec_out' means that there has been no context_switch() called. But currently 'fast_resume' is called after 'hdec_out' I think there seems to be no reason to restore non-volatiles at this point. Becasue MSR_EE is alwyas 0, 'fast_resume' will be enough like the following. It seems to work well in our HW. Please give me comments or something. - Hyeonseung Jang. diff -r 9071521d4864 xen/arch/powerpc/powerpc64/exceptions.S --- a/xen/arch/powerpc/powerpc64/exceptions.S Fri Sep 07 11:39:10 2007 +0100 +++ b/xen/arch/powerpc/powerpc64/exceptions.S Tue Sep 11 11:38:25 2007 +0900 @@ -514,6 +514,7 @@ hdec_out: hdec_out: addi r1, r1, STACK_FRAME_OVERHEAD /* restore stack to cpu_user_regs */ LOAD_GPRS r14, r15, r1 /* we clobbered r14/r15 in the loop */ +b fast_resume /* r1 points to the to-be-restored cpu_user_regs. These could be mid-hypervisor * stack (returning into elsewhere in Xen) or at the top of the stack ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
Re: [XenPPC] fast_resume instead of full_resume after hdec_out
But currently 'fast_resume' is called after 'hdec_out' It should be But currently 'full_resume' is called after 'hdec_out' Sorry for the confusion. --- Original Message --- Sender : HYEONSEUNG JANG[EMAIL PROTECTED] E5(??)/Software Laboratories/Samsung Electronics Date : Sep 11, 2007 13:22 Title : [XenPPC] fast_resume instead of full_resume after hdec_out In handling hdec exception, non-volatile registers are saved because context_switch() may be called in the do_softirq(). The fact that we reach to 'hdec_out' means that there has been no context_switch() called. But currently 'fast_resume' is called after 'hdec_out' I think there seems to be no reason to restore non-volatiles at this point. Becasue MSR_EE is alwyas 0, 'fast_resume' will be enough like the following. It seems to work well in our HW. Please give me comments or something. - Hyeonseung Jang. diff -r 9071521d4864 xen/arch/powerpc/powerpc64/exceptions.S --- a/xen/arch/powerpc/powerpc64/exceptions.S Fri Sep 07 11:39:10 2007 +0100 +++ b/xen/arch/powerpc/powerpc64/exceptions.S Tue Sep 11 11:38:25 2007 +0900 @@ -514,6 +514,7 @@ hdec_out: hdec_out: addi r1, r1, STACK_FRAME_OVERHEAD /* restore stack to cpu_user_regs */ LOAD_GPRS r14, r15, r1 /* we clobbered r14/r15 in the loop */ +b fast_resume /* r1 points to the to-be-restored cpu_user_regs. These could be mid-hypervisor * stack (returning into elsewhere in Xen) or at the top of the stack ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
