On 04.07.2012, at 17:27, Caraman Mihai Claudiu-B02008 wrote: >> -----Original Message----- >> From: Alexander Graf [mailto:agraf@xxxxxxx] >> Sent: Wednesday, July 04, 2012 5:30 PM >> To: Caraman Mihai Claudiu-B02008 >> Cc: <kvm-ppc@xxxxxxxxxxxxxxx>; KVM list; linuxppc-dev; qemu- >> ppc@xxxxxxxxxx List; Benjamin Herrenschmidt >> Subject: Re: [Qemu-ppc] [RFC PATCH 12/17] PowerPC: booke64: Add DO_KVM >> kernel hooks >> >> >> On 25.06.2012, at 14:26, Mihai Caraman wrote: >> >>> Hook DO_KVM macro to 64-bit booke in a optimal way similar to 32-bit >> booke >>> see head_fsl_booke.S file. Extend interrupt handlers' parameter list >> with >>> interrupt vector numbers to accomodate the macro. Rework Guest Doorbell >>> handler to use the proper GSRRx save/restore registers. >>> Only the bolted version of tlb miss handers is addressed now. >>> >>> Signed-off-by: Mihai Caraman <mihai.caraman@xxxxxxxxxxxxx> >>> --- >>> arch/powerpc/kernel/exceptions-64e.S | 114 ++++++++++++++++++++++++--- >> ------- >>> arch/powerpc/mm/tlb_low_64e.S | 14 +++- >>> 2 files changed, 92 insertions(+), 36 deletions(-) >>> >>> diff --git a/arch/powerpc/kernel/exceptions-64e.S >> b/arch/powerpc/kernel/exceptions-64e.S >>> index 06f7aec..a60f81f 100644 >>> --- a/arch/powerpc/kernel/exceptions-64e.S >>> +++ b/arch/powerpc/kernel/exceptions-64e.S >>> @@ -25,6 +25,8 @@ >>> #include <asm/ppc-opcode.h> >>> #include <asm/mmu.h> >>> #include <asm/hw_irq.h> >>> +#include <asm/kvm_asm.h> >>> +#include <asm/kvm_booke_hv_asm.h> >>> >>> /* XXX This will ultimately add space for a special exception save >>> * structure used to save things like SRR0/SRR1, SPRGs, MAS, etc... >>> @@ -34,13 +36,24 @@ >>> */ >>> #define SPECIAL_EXC_FRAME_SIZE INT_FRAME_SIZE >>> >>> +#ifdef CONFIG_KVM_BOOKE_HV >>> +#define KVM_BOOKE_HV_MFSPR(reg, spr) \ >>> + BEGIN_FTR_SECTION \ >>> + mfspr reg, spr; \ >>> + END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) >>> +#else >>> +#define KVM_BOOKE_HV_MFSPR(reg, spr) >>> +#endif >> >> Bleks - this is ugly. > > I agree :) But I opted to keep the optimizations done for 32-bit. > >> Do we really need to open-code the #ifdef here? > > 32-bit implementation fortunately use asm macros, we can't nest defines. > >> Can't the feature section code determine that the feature is disabled and >> just always not include the code? > > CPU_FTR_EMB_HV is set even if KVM is not configured. I don't get the point then. Why not have the whole DO_KVM masked under FTR_SECTION_IFSET(CPU_FTR_EMB_HV)? Are there book3s_64 implementations without HV? Can't we just mfspr unconditionally in DO_KVM? > >> >>> + >>> /* Exception prolog code for all exceptions */ >>> -#define EXCEPTION_PROLOG(n, type, srr0, srr1, addition) >> \ >>> +#define EXCEPTION_PROLOG(n, intnum, type, srr0, srr1, addition) >> \ >>> mtspr SPRN_SPRG_##type##_SCRATCH,r13; /* get spare registers */ >> \ >>> mfspr r13,SPRN_SPRG_PACA; /* get PACA */ \ >>> std r10,PACA_EX##type+EX_R10(r13); \ >>> std r11,PACA_EX##type+EX_R11(r13); \ >>> mfcr r10; /* save CR */ \ >>> + KVM_BOOKE_HV_MFSPR(r11,srr1); \ >>> + DO_KVM intnum,srr1; \ >> >> So if DO_KVM already knows srr1, why explicitly do something with it the >> line above, and not in DO_KVM itself? > > srr1 is used to expand the interrupt handler symbol name while r11 is used > for the actual MSR[GS] optimal check: > mtocrf 0x80, r11 Right, so basically we want #ifdef CONFIG_KVM mfspr r11, spr mtocrf 0x80, r11 beq ... #endif right? > >>> -/* Guest Doorbell */ >>> - MASKABLE_EXCEPTION(0x2c0, guest_doorbell, .unknown_exception, >> ACK_NONE) >>> +/* >>> + * Guest doorbell interrupt >>> + * This general exception use GSRRx save/restore registers >>> + */ >>> + START_EXCEPTION(guest_doorbell); >>> + EXCEPTION_PROLOG(0x2c0, BOOKE_INTERRUPT_GUEST_DBELL, GEN, >>> + SPRN_GSRR0, SPRN_GSRR1, PROLOG_ADDITION_NONE) >>> + EXCEPTION_COMMON(0x2c0, PACA_EXGEN, INTS_KEEP) >>> + addi r3,r1,STACK_FRAME_OVERHEAD >>> + bl .save_nvgprs >>> + INTS_RESTORE_HARD >>> + bl .unknown_exception >>> + b .ret_from_except >> >> This is independent of DO_KVM, right? > > Yes, just kvm_handler definitions in bookehv_interrupts.S depends on this. Then please split it out into a separate patch. > >> >>> >>> /* Guest Doorbell critical Interrupt */ >>> START_EXCEPTION(guest_doorbell_crit); >>> - CRIT_EXCEPTION_PROLOG(0x2e0, PROLOG_ADDITION_NONE) >>> + CRIT_EXCEPTION_PROLOG(0x2e0, BOOKE_INTERRUPT_GUEST_DBELL_CRIT, >>> + PROLOG_ADDITION_NONE) >> >> Shouldn't this one also use GSRR? > > No, this is a critical exception. Ah, right. Looked at the wrong bit, sorry :). > >>> >>> -.macro tlb_prolog_bolted addr >>> +.macro tlb_prolog_bolted intnum addr >>> mtspr SPRN_SPRG_TLB_SCRATCH,r13 >>> mfspr r13,SPRN_SPRG_PACA >>> std r10,PACA_EXTLB+EX_TLB_R10(r13) >>> mfcr r10 >>> std r11,PACA_EXTLB+EX_TLB_R11(r13) >>> +#ifdef CONFIG_KVM_BOOKE_HV >>> +BEGIN_FTR_SECTION >>> + mfspr r11, SPRN_SRR1 >>> +END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) >>> +#endif >> >> This thing really should vanish behind DO_KVM :) > > Then let's do it first for 32-bit ;) You could #ifdef it in DO_KVM for 64-bit for now. IIRC it's not done on 32-bit because the register value is used even beyond DO_KVM there. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
