| Message ID | 20190628200825.31049-4-cclaudio@linux.ibm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | kvmppc: Paravirtualize KVM to support ultravisor | expand |
On 2019-06-28 15:08, Claudio Carvalho wrote: > From: Ram Pai <linuxram@us.ibm.com> > > Add the ucall() function, which can be used to make ultravisor calls > with varied number of in and out arguments. Ultravisor calls can be > made > from the host or guests. > > This copies the implementation of plpar_hcall(). > > Signed-off-by: Ram Pai <linuxram@us.ibm.com> > [ Change ucall.S to not save CR, rename and move headers, build ucall.S > if CONFIG_PPC_POWERNV set, use R3 for the ucall number and add some > comments in the code ] > Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com> Reviewed-by: Janani Janakiraman <janani@linux.ibm.com> > --- > arch/powerpc/include/asm/ultravisor-api.h | 20 +++++++++++++++ > arch/powerpc/include/asm/ultravisor.h | 20 +++++++++++++++ > arch/powerpc/kernel/Makefile | 2 +- > arch/powerpc/kernel/ucall.S | 30 +++++++++++++++++++++++ > arch/powerpc/kernel/ultravisor.c | 4 +++ > 5 files changed, 75 insertions(+), 1 deletion(-) > create mode 100644 arch/powerpc/include/asm/ultravisor-api.h > create mode 100644 arch/powerpc/kernel/ucall.S > > diff --git a/arch/powerpc/include/asm/ultravisor-api.h > b/arch/powerpc/include/asm/ultravisor-api.h > new file mode 100644 > index 000000000000..49e766adabc7 > --- /dev/null > +++ b/arch/powerpc/include/asm/ultravisor-api.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Ultravisor API. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#ifndef _ASM_POWERPC_ULTRAVISOR_API_H > +#define _ASM_POWERPC_ULTRAVISOR_API_H > + > +#include <asm/hvcall.h> > + > +/* Return codes */ > +#define U_NOT_AVAILABLE H_NOT_AVAILABLE > +#define U_SUCCESS H_SUCCESS > +#define U_FUNCTION H_FUNCTION > +#define U_PARAMETER H_PARAMETER > + > +#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */ > + > diff --git a/arch/powerpc/include/asm/ultravisor.h > b/arch/powerpc/include/asm/ultravisor.h > index e5009b0d84ea..a78a2dacfd0b 100644 > --- a/arch/powerpc/include/asm/ultravisor.h > +++ b/arch/powerpc/include/asm/ultravisor.h > @@ -8,8 +8,28 @@ > #ifndef _ASM_POWERPC_ULTRAVISOR_H > #define _ASM_POWERPC_ULTRAVISOR_H > > +#include <asm/ultravisor-api.h> > + > +#if !defined(__ASSEMBLY__) > + > /* Internal functions */ > extern int early_init_dt_scan_ultravisor(unsigned long node, const > char *uname, > int depth, void *data); > > +/* API functions */ > +#define UCALL_BUFSIZE 4 > +/** > + * ucall: Make a powerpc ultravisor call. > + * @opcode: The ultravisor call to make. > + * @retbuf: Buffer to store up to 4 return arguments in. > + * > + * This call supports up to 6 arguments and 4 return arguments. Use > + * UCALL_BUFSIZE to size the return argument buffer. > + */ > +#if defined(CONFIG_PPC_POWERNV) > +long ucall(unsigned long opcode, unsigned long *retbuf, ...); > +#endif > + > +#endif /* !__ASSEMBLY__ */ > + > #endif /* _ASM_POWERPC_ULTRAVISOR_H */ > diff --git a/arch/powerpc/kernel/Makefile > b/arch/powerpc/kernel/Makefile > index f0caa302c8c0..f28baccc0a79 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -154,7 +154,7 @@ endif > > obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o > obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o > -obj-$(CONFIG_PPC_POWERNV) += ultravisor.o > +obj-$(CONFIG_PPC_POWERNV) += ultravisor.o ucall.o > > # Disable GCOV, KCOV & sanitizers in odd or sensitive code > GCOV_PROFILE_prom_init.o := n > diff --git a/arch/powerpc/kernel/ucall.S b/arch/powerpc/kernel/ucall.S > new file mode 100644 > index 000000000000..1678f6eb7230 > --- /dev/null > +++ b/arch/powerpc/kernel/ucall.S > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Generic code to perform an ultravisor call. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#include <asm/ppc_asm.h> > + > +/* > + * This function is based on the plpar_hcall() > + */ > +_GLOBAL_TOC(ucall) > + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ > + mr r4,r5 > + mr r5,r6 > + mr r6,r7 > + mr r7,r8 > + mr r8,r9 > + mr r9,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) > + > + blr /* Return r3 = status */ > diff --git a/arch/powerpc/kernel/ultravisor.c > b/arch/powerpc/kernel/ultravisor.c > index dc6021f63c97..02ddf79a9522 100644 > --- a/arch/powerpc/kernel/ultravisor.c > +++ b/arch/powerpc/kernel/ultravisor.c > @@ -8,10 +8,14 @@ > #include <linux/init.h> > #include <linux/printk.h> > #include <linux/string.h> > +#include <linux/export.h> > > #include <asm/ultravisor.h> > #include <asm/firmware.h> > > +/* in ucall.S */ > +EXPORT_SYMBOL_GPL(ucall); > + > int __init early_init_dt_scan_ultravisor(unsigned long node, const > char *uname, > int depth, void *data) > {
Claudio Carvalho <cclaudio@linux.ibm.com> writes: > From: Ram Pai <linuxram@us.ibm.com> > > Add the ucall() function, which can be used to make ultravisor calls > with varied number of in and out arguments. Ultravisor calls can be made > from the host or guests. > > This copies the implementation of plpar_hcall(). .. with quite a few changes? This is one of the things I'd like to see in a Documentation file, so that people can review the implementation vs the specification. > Signed-off-by: Ram Pai <linuxram@us.ibm.com> > [ Change ucall.S to not save CR, rename and move headers, build ucall.S > if CONFIG_PPC_POWERNV set, use R3 for the ucall number and add some > comments in the code ] Why are we not saving CR? See previous comment about Documentation :) > Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com> > --- > arch/powerpc/include/asm/ultravisor-api.h | 20 +++++++++++++++ > arch/powerpc/include/asm/ultravisor.h | 20 +++++++++++++++ > arch/powerpc/kernel/Makefile | 2 +- > arch/powerpc/kernel/ucall.S | 30 +++++++++++++++++++++++ > arch/powerpc/kernel/ultravisor.c | 4 +++ > 5 files changed, 75 insertions(+), 1 deletion(-) > create mode 100644 arch/powerpc/include/asm/ultravisor-api.h > create mode 100644 arch/powerpc/kernel/ucall.S > > diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h > new file mode 100644 > index 000000000000..49e766adabc7 > --- /dev/null > +++ b/arch/powerpc/include/asm/ultravisor-api.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Ultravisor API. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#ifndef _ASM_POWERPC_ULTRAVISOR_API_H > +#define _ASM_POWERPC_ULTRAVISOR_API_H > + > +#include <asm/hvcall.h> > + > +/* Return codes */ > +#define U_NOT_AVAILABLE H_NOT_AVAILABLE > +#define U_SUCCESS H_SUCCESS > +#define U_FUNCTION H_FUNCTION > +#define U_PARAMETER H_PARAMETER Is there any benefit in redefining these? > diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h > index e5009b0d84ea..a78a2dacfd0b 100644 > --- a/arch/powerpc/include/asm/ultravisor.h > +++ b/arch/powerpc/include/asm/ultravisor.h > @@ -8,8 +8,28 @@ > #ifndef _ASM_POWERPC_ULTRAVISOR_H > #define _ASM_POWERPC_ULTRAVISOR_H > > +#include <asm/ultravisor-api.h> > + > +#if !defined(__ASSEMBLY__) Just #ifndef is fine. > /* Internal functions */ How is it internal? > extern int early_init_dt_scan_ultravisor(unsigned long node, const char *uname, > int depth, void *data); > > +/* API functions */ > +#define UCALL_BUFSIZE 4 Please don't copy this design from the hcall code, it has led to bugs in the past. See my (still unmerged) attempt to fix this for the hcall case: https://patchwork.ozlabs.org/patch/683577/ Basically instead of asking callers nicely to define a certain sized buffer, and them forgetting, define a proper type that has the right size. > +/** > + * ucall: Make a powerpc ultravisor call. > + * @opcode: The ultravisor call to make. > + * @retbuf: Buffer to store up to 4 return arguments in. > + * > + * This call supports up to 6 arguments and 4 return arguments. Use > + * UCALL_BUFSIZE to size the return argument buffer. > + */ > +#if defined(CONFIG_PPC_POWERNV) #ifdef > +long ucall(unsigned long opcode, unsigned long *retbuf, ...); > +#endif > + > +#endif /* !__ASSEMBLY__ */ > + > #endif /* _ASM_POWERPC_ULTRAVISOR_H */ > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index f0caa302c8c0..f28baccc0a79 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -154,7 +154,7 @@ endif > > obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o > obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o > -obj-$(CONFIG_PPC_POWERNV) += ultravisor.o > +obj-$(CONFIG_PPC_POWERNV) += ultravisor.o ucall.o Same comment about being platforms/powernv ? > > diff --git a/arch/powerpc/kernel/ucall.S b/arch/powerpc/kernel/ucall.S > new file mode 100644 > index 000000000000..1678f6eb7230 > --- /dev/null > +++ b/arch/powerpc/kernel/ucall.S > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Generic code to perform an ultravisor call. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#include <asm/ppc_asm.h> > + > +/* > + * This function is based on the plpar_hcall() I don't think it meaningfully is any more. > + */ > +_GLOBAL_TOC(ucall) You don't need the TOC setup here (unless a later patch does?). > + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ > + mr r4,r5 > + mr r5,r6 > + mr r6,r7 > + mr r7,r8 > + mr r8,r9 > + mr r9,r10 Below you space the arguments, here you don't. Pick one or the other please. > + > + 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) > + > + blr /* Return r3 = status */ > diff --git a/arch/powerpc/kernel/ultravisor.c b/arch/powerpc/kernel/ultravisor.c > index dc6021f63c97..02ddf79a9522 100644 > --- a/arch/powerpc/kernel/ultravisor.c > +++ b/arch/powerpc/kernel/ultravisor.c > @@ -8,10 +8,14 @@ > #include <linux/init.h> > #include <linux/printk.h> > #include <linux/string.h> > +#include <linux/export.h> > > #include <asm/ultravisor.h> > #include <asm/firmware.h> > > +/* in ucall.S */ > +EXPORT_SYMBOL_GPL(ucall); This should be in ucall.S cheers
Claudio Carvalho's on June 29, 2019 6:08 am: > From: Ram Pai <linuxram@us.ibm.com> > > Add the ucall() function, which can be used to make ultravisor calls > with varied number of in and out arguments. Ultravisor calls can be made > from the host or guests. > > This copies the implementation of plpar_hcall(). > > Signed-off-by: Ram Pai <linuxram@us.ibm.com> > [ Change ucall.S to not save CR, rename and move headers, build ucall.S > if CONFIG_PPC_POWERNV set, use R3 for the ucall number and add some > comments in the code ] > Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com> > --- > arch/powerpc/include/asm/ultravisor-api.h | 20 +++++++++++++++ > arch/powerpc/include/asm/ultravisor.h | 20 +++++++++++++++ > arch/powerpc/kernel/Makefile | 2 +- > arch/powerpc/kernel/ucall.S | 30 +++++++++++++++++++++++ > arch/powerpc/kernel/ultravisor.c | 4 +++ > 5 files changed, 75 insertions(+), 1 deletion(-) > create mode 100644 arch/powerpc/include/asm/ultravisor-api.h > create mode 100644 arch/powerpc/kernel/ucall.S > > diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h > new file mode 100644 > index 000000000000..49e766adabc7 > --- /dev/null > +++ b/arch/powerpc/include/asm/ultravisor-api.h > @@ -0,0 +1,20 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Ultravisor API. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#ifndef _ASM_POWERPC_ULTRAVISOR_API_H > +#define _ASM_POWERPC_ULTRAVISOR_API_H > + > +#include <asm/hvcall.h> > + > +/* Return codes */ > +#define U_NOT_AVAILABLE H_NOT_AVAILABLE > +#define U_SUCCESS H_SUCCESS > +#define U_FUNCTION H_FUNCTION > +#define U_PARAMETER H_PARAMETER > + > +#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */ > + > diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h > index e5009b0d84ea..a78a2dacfd0b 100644 > --- a/arch/powerpc/include/asm/ultravisor.h > +++ b/arch/powerpc/include/asm/ultravisor.h > @@ -8,8 +8,28 @@ > #ifndef _ASM_POWERPC_ULTRAVISOR_H > #define _ASM_POWERPC_ULTRAVISOR_H > > +#include <asm/ultravisor-api.h> > + > +#if !defined(__ASSEMBLY__) > + > /* Internal functions */ > extern int early_init_dt_scan_ultravisor(unsigned long node, const char *uname, > int depth, void *data); > > +/* API functions */ > +#define UCALL_BUFSIZE 4 > +/** > + * ucall: Make a powerpc ultravisor call. > + * @opcode: The ultravisor call to make. > + * @retbuf: Buffer to store up to 4 return arguments in. > + * > + * This call supports up to 6 arguments and 4 return arguments. Use > + * UCALL_BUFSIZE to size the return argument buffer. > + */ > +#if defined(CONFIG_PPC_POWERNV) > +long ucall(unsigned long opcode, unsigned long *retbuf, ...); > +#endif > + > +#endif /* !__ASSEMBLY__ */ > + > #endif /* _ASM_POWERPC_ULTRAVISOR_H */ > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index f0caa302c8c0..f28baccc0a79 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -154,7 +154,7 @@ endif > > obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o > obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o > -obj-$(CONFIG_PPC_POWERNV) += ultravisor.o > +obj-$(CONFIG_PPC_POWERNV) += ultravisor.o ucall.o > > # Disable GCOV, KCOV & sanitizers in odd or sensitive code > GCOV_PROFILE_prom_init.o := n > diff --git a/arch/powerpc/kernel/ucall.S b/arch/powerpc/kernel/ucall.S > new file mode 100644 > index 000000000000..1678f6eb7230 > --- /dev/null > +++ b/arch/powerpc/kernel/ucall.S > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Generic code to perform an ultravisor call. > + * > + * Copyright 2019, IBM Corporation. > + * > + */ > +#include <asm/ppc_asm.h> > + > +/* > + * This function is based on the plpar_hcall() A better comment might be to specify calling convention. > + */ > +_GLOBAL_TOC(ucall) > + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ > + mr r4,r5 > + mr r5,r6 > + mr r6,r7 > + mr r7,r8 > + mr r8,r9 > + mr r9,r10 I guess this is fine, is there any particular reason that you made the call convention this way rather than leaving regs in place and r4 is a scratch? > + > + 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) > +
On 7/11/19 9:57 AM, Michael Ellerman wrote: > Claudio Carvalho <cclaudio@linux.ibm.com> writes: >> From: Ram Pai <linuxram@us.ibm.com> >> >> Add the ucall() function, which can be used to make ultravisor calls >> with varied number of in and out arguments. Ultravisor calls can be made >> from the host or guests. >> >> This copies the implementation of plpar_hcall(). > .. with quite a few changes? > > This is one of the things I'd like to see in a Documentation file, so > that people can review the implementation vs the specification. I will document this (and other things) in a file under Documentation/powerpc. > >> Signed-off-by: Ram Pai <linuxram@us.ibm.com> >> [ Change ucall.S to not save CR, rename and move headers, build ucall.S >> if CONFIG_PPC_POWERNV set, use R3 for the ucall number and add some >> comments in the code ] > Why are we not saving CR? See previous comment about Documentation :) > >> Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com> >> --- >> arch/powerpc/include/asm/ultravisor-api.h | 20 +++++++++++++++ >> arch/powerpc/include/asm/ultravisor.h | 20 +++++++++++++++ >> arch/powerpc/kernel/Makefile | 2 +- >> arch/powerpc/kernel/ucall.S | 30 +++++++++++++++++++++++ >> arch/powerpc/kernel/ultravisor.c | 4 +++ >> 5 files changed, 75 insertions(+), 1 deletion(-) >> create mode 100644 arch/powerpc/include/asm/ultravisor-api.h >> create mode 100644 arch/powerpc/kernel/ucall.S >> >> diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h >> new file mode 100644 >> index 000000000000..49e766adabc7 >> --- /dev/null >> +++ b/arch/powerpc/include/asm/ultravisor-api.h >> @@ -0,0 +1,20 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * Ultravisor API. >> + * >> + * Copyright 2019, IBM Corporation. >> + * >> + */ >> +#ifndef _ASM_POWERPC_ULTRAVISOR_API_H >> +#define _ASM_POWERPC_ULTRAVISOR_API_H >> + >> +#include <asm/hvcall.h> >> + >> +/* Return codes */ >> +#define U_NOT_AVAILABLE H_NOT_AVAILABLE >> +#define U_SUCCESS H_SUCCESS >> +#define U_FUNCTION H_FUNCTION >> +#define U_PARAMETER H_PARAMETER > Is there any benefit in redefining these? > >> diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h >> index e5009b0d84ea..a78a2dacfd0b 100644 >> --- a/arch/powerpc/include/asm/ultravisor.h >> +++ b/arch/powerpc/include/asm/ultravisor.h >> @@ -8,8 +8,28 @@ >> #ifndef _ASM_POWERPC_ULTRAVISOR_H >> #define _ASM_POWERPC_ULTRAVISOR_H >> >> +#include <asm/ultravisor-api.h> >> + >> +#if !defined(__ASSEMBLY__) > Just #ifndef is fine. > >> /* Internal functions */ > How is it internal? > >> extern int early_init_dt_scan_ultravisor(unsigned long node, const char *uname, >> int depth, void *data); >> >> +/* API functions */ >> +#define UCALL_BUFSIZE 4 > Please don't copy this design from the hcall code, it has led to bugs in > the past. > > See my (still unmerged) attempt to fix this for the hcall case: > https://patchwork.ozlabs.org/patch/683577/ > > Basically instead of asking callers nicely to define a certain sized > buffer, and them forgetting, define a proper type that has the right size. I will keep that in mind. For now I think we don't need that since the v5 will have ucall_norets() instead. > >> +/** >> + * ucall: Make a powerpc ultravisor call. >> + * @opcode: The ultravisor call to make. >> + * @retbuf: Buffer to store up to 4 return arguments in. >> + * >> + * This call supports up to 6 arguments and 4 return arguments. Use >> + * UCALL_BUFSIZE to size the return argument buffer. >> + */ >> +#if defined(CONFIG_PPC_POWERNV) > #ifdef > >> +long ucall(unsigned long opcode, unsigned long *retbuf, ...); >> +#endif >> + >> +#endif /* !__ASSEMBLY__ */ >> + >> #endif /* _ASM_POWERPC_ULTRAVISOR_H */ >> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile >> index f0caa302c8c0..f28baccc0a79 100644 >> --- a/arch/powerpc/kernel/Makefile >> +++ b/arch/powerpc/kernel/Makefile >> @@ -154,7 +154,7 @@ endif >> >> obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o >> obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o >> -obj-$(CONFIG_PPC_POWERNV) += ultravisor.o >> +obj-$(CONFIG_PPC_POWERNV) += ultravisor.o ucall.o > Same comment about being platforms/powernv ? >> diff --git a/arch/powerpc/kernel/ucall.S b/arch/powerpc/kernel/ucall.S >> new file mode 100644 >> index 000000000000..1678f6eb7230 >> --- /dev/null >> +++ b/arch/powerpc/kernel/ucall.S >> @@ -0,0 +1,30 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * Generic code to perform an ultravisor call. >> + * >> + * Copyright 2019, IBM Corporation. >> + * >> + */ >> +#include <asm/ppc_asm.h> >> + >> +/* >> + * This function is based on the plpar_hcall() > I don't think it meaningfully is any more. > >> + */ >> +_GLOBAL_TOC(ucall) > You don't need the TOC setup here (unless a later patch does?). > >> + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ >> + mr r4,r5 >> + mr r5,r6 >> + mr r6,r7 >> + mr r7,r8 >> + mr r8,r9 >> + mr r9,r10 > Below you space the arguments, here you don't. Pick one or the other please. > >> + >> + 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) >> + >> + blr /* Return r3 = status */ >> diff --git a/arch/powerpc/kernel/ultravisor.c b/arch/powerpc/kernel/ultravisor.c >> index dc6021f63c97..02ddf79a9522 100644 >> --- a/arch/powerpc/kernel/ultravisor.c >> +++ b/arch/powerpc/kernel/ultravisor.c >> @@ -8,10 +8,14 @@ >> #include <linux/init.h> >> #include <linux/printk.h> >> #include <linux/string.h> >> +#include <linux/export.h> >> >> #include <asm/ultravisor.h> >> #include <asm/firmware.h> >> >> +/* in ucall.S */ >> +EXPORT_SYMBOL_GPL(ucall); > This should be in ucall.S Here I'm following the same way that hypercall wrapper symbols are exported. Last time I tried to export that in ucall.S the linker complained that the ucall symbol will not be versioned. Something like this: https://patchwork.kernel.org/patch/9452759/ Thanks, Claudio > > cheers
Claudio Carvalho <cclaudio@linux.ibm.com> writes: > On 7/11/19 9:57 AM, Michael Ellerman wrote: >> Claudio Carvalho <cclaudio@linux.ibm.com> writes: >>> From: Ram Pai <linuxram@us.ibm.com> >>> >>> Add the ucall() function, which can be used to make ultravisor calls >>> with varied number of in and out arguments. Ultravisor calls can be made >>> from the host or guests. >>> >>> This copies the implementation of plpar_hcall(). >> .. with quite a few changes? >> >> This is one of the things I'd like to see in a Documentation file, so >> that people can review the implementation vs the specification. > > I will document this (and other things) in a file under Documentation/powerpc. Thanks. >>> +/* API functions */ >>> +#define UCALL_BUFSIZE 4 >> Please don't copy this design from the hcall code, it has led to bugs in >> the past. >> >> See my (still unmerged) attempt to fix this for the hcall case: >> https://patchwork.ozlabs.org/patch/683577/ >> >> Basically instead of asking callers nicely to define a certain sized >> buffer, and them forgetting, define a proper type that has the right size. > > I will keep that in mind. For now I think we don't need that since the v5 > will have ucall_norets() instead. OK. >>> diff --git a/arch/powerpc/kernel/ultravisor.c b/arch/powerpc/kernel/ultravisor.c >>> index dc6021f63c97..02ddf79a9522 100644 >>> --- a/arch/powerpc/kernel/ultravisor.c >>> +++ b/arch/powerpc/kernel/ultravisor.c >>> @@ -8,10 +8,14 @@ >>> #include <linux/init.h> >>> #include <linux/printk.h> >>> #include <linux/string.h> >>> +#include <linux/export.h> >>> >>> #include <asm/ultravisor.h> >>> #include <asm/firmware.h> >>> >>> +/* in ucall.S */ >>> +EXPORT_SYMBOL_GPL(ucall); >> This should be in ucall.S > > Here I'm following the same way that hypercall wrapper symbols are exported. Yeah we used to not be able to export from .S but that was fixed a few years ago. > Last time I tried to export that in ucall.S the linker complained that the > ucall > symbol will not be versioned. Something like this: > https://patchwork.kernel.org/patch/9452759/ I think you just need to include <asm/export.h> in the .S ? cheers
diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h new file mode 100644 index 000000000000..49e766adabc7 --- /dev/null +++ b/arch/powerpc/include/asm/ultravisor-api.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Ultravisor API. + * + * Copyright 2019, IBM Corporation. + * + */ +#ifndef _ASM_POWERPC_ULTRAVISOR_API_H +#define _ASM_POWERPC_ULTRAVISOR_API_H + +#include <asm/hvcall.h> + +/* Return codes */ +#define U_NOT_AVAILABLE H_NOT_AVAILABLE +#define U_SUCCESS H_SUCCESS +#define U_FUNCTION H_FUNCTION +#define U_PARAMETER H_PARAMETER + +#endif /* _ASM_POWERPC_ULTRAVISOR_API_H */ + diff --git a/arch/powerpc/include/asm/ultravisor.h b/arch/powerpc/include/asm/ultravisor.h index e5009b0d84ea..a78a2dacfd0b 100644 --- a/arch/powerpc/include/asm/ultravisor.h +++ b/arch/powerpc/include/asm/ultravisor.h @@ -8,8 +8,28 @@ #ifndef _ASM_POWERPC_ULTRAVISOR_H #define _ASM_POWERPC_ULTRAVISOR_H +#include <asm/ultravisor-api.h> + +#if !defined(__ASSEMBLY__) + /* Internal functions */ extern int early_init_dt_scan_ultravisor(unsigned long node, const char *uname, int depth, void *data); +/* API functions */ +#define UCALL_BUFSIZE 4 +/** + * ucall: Make a powerpc ultravisor call. + * @opcode: The ultravisor call to make. + * @retbuf: Buffer to store up to 4 return arguments in. + * + * This call supports up to 6 arguments and 4 return arguments. Use + * UCALL_BUFSIZE to size the return argument buffer. + */ +#if defined(CONFIG_PPC_POWERNV) +long ucall(unsigned long opcode, unsigned long *retbuf, ...); +#endif + +#endif /* !__ASSEMBLY__ */ + #endif /* _ASM_POWERPC_ULTRAVISOR_H */ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index f0caa302c8c0..f28baccc0a79 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -154,7 +154,7 @@ endif obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o -obj-$(CONFIG_PPC_POWERNV) += ultravisor.o +obj-$(CONFIG_PPC_POWERNV) += ultravisor.o ucall.o # Disable GCOV, KCOV & sanitizers in odd or sensitive code GCOV_PROFILE_prom_init.o := n diff --git a/arch/powerpc/kernel/ucall.S b/arch/powerpc/kernel/ucall.S new file mode 100644 index 000000000000..1678f6eb7230 --- /dev/null +++ b/arch/powerpc/kernel/ucall.S @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Generic code to perform an ultravisor call. + * + * Copyright 2019, IBM Corporation. + * + */ +#include <asm/ppc_asm.h> + +/* + * This function is based on the plpar_hcall() + */ +_GLOBAL_TOC(ucall) + std r4,STK_PARAM(R4)(r1) /* Save ret buffer */ + mr r4,r5 + mr r5,r6 + mr r6,r7 + mr r7,r8 + mr r8,r9 + mr r9,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) + + blr /* Return r3 = status */ diff --git a/arch/powerpc/kernel/ultravisor.c b/arch/powerpc/kernel/ultravisor.c index dc6021f63c97..02ddf79a9522 100644 --- a/arch/powerpc/kernel/ultravisor.c +++ b/arch/powerpc/kernel/ultravisor.c @@ -8,10 +8,14 @@ #include <linux/init.h> #include <linux/printk.h> #include <linux/string.h> +#include <linux/export.h> #include <asm/ultravisor.h> #include <asm/firmware.h> +/* in ucall.S */ +EXPORT_SYMBOL_GPL(ucall); + int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname, int depth, void *data) {