| Message ID | 1548172784-27414-2-git-send-email-linuxram@us.ibm.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | KVM: PPC: Paravirtualize KVM to support Ultravisor | expand |
On Tue, Jan 22, 2019 at 07:59:32AM -0800, Ram Pai wrote: > plpar_ucall() function can now be used to make ucalls > with varied number of in and out arguments. It handles > 4 out arguments and a lot of in arguments. > > copies the implementation of plpar_hcall(). > > Signed-off-by: Ram Pai <linuxram@us.ibm.com> > --- > arch/powerpc/platforms/powernv/Makefile | 1 + > arch/powerpc/platforms/powernv/uvCall.S | 41 +++++++++++++++++++++++++++++++++ I don't think arch/powerpc/platforms/powernv is the right place for this, since we will also need to do ucalls from a secure guest and its kernel may not have CONFIG_PPC_POWERNV=y. Also, the "plpar_" prefix gives rise to a cognitive dissonance, because "plpar" is short for pSeries logical partition, and we definitely are not in a pSeries logical partition here. > +_GLOBAL_TOC(plpar_ucall) > + > + mfcr r0 > + stw r0,8(r1) > + mr r0,r3 > + > + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ > + > + mr r3,r5 > + mr r4,r6 > + mr r5,r7 > + mr r6,r8 > + mr r7,r9 > + mr r8,r10 > + > + sc 2 /* invoke the ultravisor */ > + > + ld r12,STK_PARAM(R4)(r1) > + std r4, 0(r12) > + std r5, 8(r12) > + std r6, 16(r12) > + std r7, 24(r12) > + > + lwz r0,8(r1) > + mtcrf 0xff,r0 > + > + blr /* return r3 = status */ So we save/restore CR across the ucall, but not LR. Do we really not trust the ultravisor to preserve the non-volatile CR fields, or is it just that you were copying plpar_hcall()? Either way it deserves a note in the patch description. Paul.
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile index b540ce8e..5ae1df02 100644 --- a/arch/powerpc/platforms/powernv/Makefile +++ b/arch/powerpc/platforms/powernv/Makefile @@ -4,6 +4,7 @@ obj-y += opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o obj-y += rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o obj-y += opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o obj-y += opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o +obj-y += uvCall.o obj-$(CONFIG_SMP) += smp.o subcore.o subcore-asm.o obj-$(CONFIG_PCI) += pci.o pci-ioda.o npu-dma.o pci-ioda-tce.o diff --git a/arch/powerpc/platforms/powernv/uvCall.S b/arch/powerpc/platforms/powernv/uvCall.S new file mode 100644 index 0000000..a5e976a --- /dev/null +++ b/arch/powerpc/platforms/powernv/uvCall.S @@ -0,0 +1,41 @@ +/* + * This file contains the generic code to perform a ultracall. + * + * Copyright IBM Corporation 2019. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include <linux/jump_label.h> +#include <asm/ppc_asm.h> +#include <asm/asm-offsets.h> + +_GLOBAL_TOC(plpar_ucall) + + mfcr r0 + stw r0,8(r1) + mr r0,r3 + + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ + + mr r3,r5 + mr r4,r6 + mr r5,r7 + mr r6,r8 + mr r7,r9 + mr r8,r10 + + sc 2 /* invoke the ultravisor */ + + ld r12,STK_PARAM(R4)(r1) + std r4, 0(r12) + std r5, 8(r12) + std r6, 16(r12) + std r7, 24(r12) + + lwz r0,8(r1) + mtcrf 0xff,r0 + + blr /* return r3 = status */
plpar_ucall() function can now be used to make ucalls with varied number of in and out arguments. It handles 4 out arguments and a lot of in arguments. copies the implementation of plpar_hcall(). Signed-off-by: Ram Pai <linuxram@us.ibm.com> --- arch/powerpc/platforms/powernv/Makefile | 1 + arch/powerpc/platforms/powernv/uvCall.S | 41 +++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) create mode 100644 arch/powerpc/platforms/powernv/uvCall.S