RE: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
-Original Message- From: Wood Scott-B07421 Sent: Thursday, September 13, 2012 12:54 AM To: Alexander Graf Cc: Caraman Mihai Claudiu-B02008; kvm-...@vger.kernel.org; linuxppc- d...@lists.ozlabs.org; k...@vger.kernel.org Subject: Re: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro On 09/12/2012 04:45 PM, Alexander Graf wrote: On 12.09.2012, at 23:38, Scott Wood scottw...@freescale.com wrote: On 09/12/2012 01:56 PM, Alexander Graf wrote: On 12.09.2012, at 15:18, Mihai Caraman mihai.cara...@freescale.com wrote: The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Not sure I understand what you're trying to achieve here. Please elaborate ;) On 64-bit book3e we compile multiple versions of the TLB miss handlers, and choose from them at runtime. The exception handler patching is active in __early_init_mmu() function powerpc/mm/tlb_nohash.c for quite a few years. For tlb miss exceptions there are three handler versions: standard, HW tablewalk and bolted. I posted a patch to add another variant, for e6500-style hardware tablewalk, which shares the bolted prolog/epilog (besides prolog/epilog performance, e6500 is incompatible with the IBM tablewalk code for various reasons). That caused us to have two DO_KVMs for the same exception type. Sorry, I missed to cc kvm-ppc mailist when I replayed to that discussion thread. -Mike ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
On 09/12/2012 03:18 PM, Mihai Caraman wrote: The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Use a rare label number to avoid conflicts with the calling contexts. Signed-off-by: Mihai Caraman mihai.cara...@freescale.com Thanks, applied to kvm-ppc-next. Alex ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Use a rare label number to avoid conflicts with the calling contexts. Signed-off-by: Mihai Caraman mihai.cara...@freescale.com --- arch/powerpc/include/asm/kvm_booke_hv_asm.h |4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_booke_hv_asm.h b/arch/powerpc/include/asm/kvm_booke_hv_asm.h index 30a600f..a37a12a 100644 --- a/arch/powerpc/include/asm/kvm_booke_hv_asm.h +++ b/arch/powerpc/include/asm/kvm_booke_hv_asm.h @@ -38,9 +38,9 @@ #ifdef CONFIG_KVM_BOOKE_HV BEGIN_FTR_SECTION mtocrf 0x80, r11 /* check MSR[GS] without clobbering reg */ - bf 3, kvmppc_resume_\intno\()_\srr1 + bf 3, 1975f b kvmppc_handler_\intno\()_\srr1 -kvmppc_resume_\intno\()_\srr1: +1975: END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) #endif .endm -- 1.7.4.1 ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
On 12.09.2012, at 15:18, Mihai Caraman mihai.cara...@freescale.com wrote: The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Not sure I understand what you're trying to achieve here. Please elaborate ;) Alex Use a rare label number to avoid conflicts with the calling contexts. Signed-off-by: Mihai Caraman mihai.cara...@freescale.com --- arch/powerpc/include/asm/kvm_booke_hv_asm.h |4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_booke_hv_asm.h b/arch/powerpc/include/asm/kvm_booke_hv_asm.h index 30a600f..a37a12a 100644 --- a/arch/powerpc/include/asm/kvm_booke_hv_asm.h +++ b/arch/powerpc/include/asm/kvm_booke_hv_asm.h @@ -38,9 +38,9 @@ #ifdef CONFIG_KVM_BOOKE_HV BEGIN_FTR_SECTION mtocrf0x80, r11/* check MSR[GS] without clobbering reg */ -bf3, kvmppc_resume_\intno\()_\srr1 +bf3, 1975f bkvmppc_handler_\intno\()_\srr1 -kvmppc_resume_\intno\()_\srr1: +1975: END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) #endif .endm -- 1.7.4.1 -- To unsubscribe from this list: send the line unsubscribe kvm-ppc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
On 09/12/2012 01:56 PM, Alexander Graf wrote: On 12.09.2012, at 15:18, Mihai Caraman mihai.cara...@freescale.com wrote: The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Not sure I understand what you're trying to achieve here. Please elaborate ;) On 64-bit book3e we compile multiple versions of the TLB miss handlers, and choose from them at runtime. Without this patch, we get duplicate label errors if more than one variant of the same exception uses DO_KVM. -Scott ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
On 12.09.2012, at 23:38, Scott Wood scottw...@freescale.com wrote: On 09/12/2012 01:56 PM, Alexander Graf wrote: On 12.09.2012, at 15:18, Mihai Caraman mihai.cara...@freescale.com wrote: The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Not sure I understand what you're trying to achieve here. Please elaborate ;) On 64-bit book3e we compile multiple versions of the TLB miss handlers, and choose from them at runtime. Why? Without this patch, we get duplicate label errors if more than one variant of the same exception uses DO_KVM. Makes sense. The proposed solution also looks good. Just quickly walk me through the reasoning for the runtime check again please. Alex -Scott -- To unsubscribe from this list: send the line unsubscribe kvm-ppc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] KVM: PPC: bookehv: Allow duplicate calls of DO_KVM macro
On 09/12/2012 04:45 PM, Alexander Graf wrote: On 12.09.2012, at 23:38, Scott Wood scottw...@freescale.com wrote: On 09/12/2012 01:56 PM, Alexander Graf wrote: On 12.09.2012, at 15:18, Mihai Caraman mihai.cara...@freescale.com wrote: The current form of DO_KVM macro restricts its use to one call per input parameter set. This is caused by kvmppc_resume_\intno\()_\srr1 symbol definition. Duplicate calls of DO_KVM are required by distinct implementations of exeption handlers which are delegated at runtime. Not sure I understand what you're trying to achieve here. Please elaborate ;) On 64-bit book3e we compile multiple versions of the TLB miss handlers, and choose from them at runtime. Why? Because one size does not fit all, and we try to not force a separate kernel build based on what sort of TLB miss handler a piece of hardware wants. Some of the differences are too large to be sanely handled by feature fixups. Without this patch, we get duplicate label errors if more than one variant of the same exception uses DO_KVM. Makes sense. The proposed solution also looks good. Just quickly walk me through the reasoning for the runtime check again please. To start with, you have a TLB miss handler for when partial hardware tablewalk is used (only the final page table level is looked up in hardware, so we still need a TLB miss handler to load indirect entries), and one where that feature is not available. Then you have the bolted variant used by e5500, which is faster than the generic version because it doesn't have to deal with recursive faults. So far the bolted version is the only one with DO_KVM. I posted a patch to add another variant, for e6500-style hardware tablewalk, which shares the bolted prolog/epilog (besides prolog/epilog performance, e6500 is incompatible with the IBM tablewalk code for various reasons). That caused us to have two DO_KVMs for the same exception type. -Scott ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
