Patchwork kvmppc: add hypercall infrastructure - guest part v3

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Submitter ehrhardt@linux.vnet.ibm.com
Date Sept. 16, 2008, 6:27 a.m.
Message ID <1221546450-15761-3-git-send-email-ehrhardt@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/289/
State Changes Requested, archived
Delegated to: Hollis Blanchard
Headers show

Comments

ehrhardt@linux.vnet.ibm.com - Sept. 16, 2008, 6:27 a.m.
From: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>

This adds the guest portion of the hypercall infrastructure.

Version 3 now follows the beat ABI, but proposes a new implementation style as
static inline asm functions instead of pure assembler code. That should allow
the compiler to be more flexible and therefore a better optimization.

If people agree on that new implementation style we might merge this code.
The current implementation of beat style hypercalls can be found in
arch/powerpc/platforms/cell/beat_hvCall.S

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Kumar Gala - Oct. 13, 2008, 4:42 p.m.
On Sep 16, 2008, at 1:27 AM, ehrhardt@linux.vnet.ibm.com wrote:

> From: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
>
> This adds the guest portion of the hypercall infrastructure.
>
> Version 3 now follows the beat ABI, but proposes a new  
> implementation style as
> static inline asm functions instead of pure assembler code. That  
> should allow
> the compiler to be more flexible and therefore a better optimization.
>
> If people agree on that new implementation style we might merge this  
> code.
> The current implementation of beat style hypercalls can be found in
> arch/powerpc/platforms/cell/beat_hvCall.S
>
> Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
> ---
>
> [diffstat]
> epapr_hcalls.h |   59 +++++++++++++++++++++++++++++++++++++++++++++++ 
> ++++++++++
> 1 file changed, 59 insertions(+)
>
> [diff]
>
> diff --git a/include/asm-powerpc/epapr_hcalls.h b/include/asm- 
> powerpc/epapr_hcalls.h
> new file mode 100644
> --- /dev/null
> +++ b/include/asm-powerpc/epapr_hcalls.h
> @@ -0,0 +1,59 @@
> +/*
> + * This program is free software; you can redistribute it and/or  
> modify
> + * it under the terms of the GNU General Public License, version 2,  
> as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA   
> 02110-1301, USA.
> + *
> + * Copyright IBM Corp. 2008
> + *
> + * Authors:
> + * 	Christian Ehrhardt <ehrhardt@de.ibm.com>
> + */
> +
> +#ifndef __POWERPC_EPAPR_HCALLS_H__
> +#define __POWERPC_EPAPR_HCALLS_H__
> +
> +#ifdef __KERNEL__
> +
> +/* Hypercalls use the beat ABI */
> +#define KVM_HYPERCALL_BIN 0x44000022

Any reason this isn't 'sc' ?

Also, can we make this "sc 1" so its works when we have HW hypervisor  
support?

- k
Hollis Blanchard - Oct. 13, 2008, 5:29 p.m.
On Mon, 2008-10-13 at 11:42 -0500, Kumar Gala wrote:
> > +
> > +/* Hypercalls use the beat ABI */
> > +#define KVM_HYPERCALL_BIN 0x44000022
> 
> Any reason this isn't 'sc' ?
> 
> Also, can we make this "sc 1" so its works when we have HW hypervisor  
> support?

Actually, it is "sc 1".

Many versions of as (including 2.16.1) don't recognize that instruction.
This is the standard workaround for situations like that.
Kumar Gala - Oct. 13, 2008, 5:44 p.m.
On Oct 13, 2008, at 12:29 PM, Hollis Blanchard wrote:

> On Mon, 2008-10-13 at 11:42 -0500, Kumar Gala wrote:
>>> +
>>> +/* Hypercalls use the beat ABI */
>>> +#define KVM_HYPERCALL_BIN 0x44000022
>>
>> Any reason this isn't 'sc' ?
>>
>> Also, can we make this "sc 1" so its works when we have HW hypervisor
>> support?
>
> Actually, it is "sc 1".
>
> Many versions of as (including 2.16.1) don't recognize that  
> instruction.
> This is the standard workaround for situations like that.

Ahh, we'll than can we add that to the comment, and rename  
'KVM_HYPERCALL_BIN' to something like 'EPAPR_HYPERCALL_INSTR'

- k

Patch

diff --git a/include/asm-powerpc/epapr_hcalls.h b/include/asm-powerpc/epapr_hcalls.h
new file mode 100644
--- /dev/null
+++ b/include/asm-powerpc/epapr_hcalls.h
@@ -0,0 +1,59 @@ 
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * Authors:
+ * 	Christian Ehrhardt <ehrhardt@de.ibm.com>
+ */
+
+#ifndef __POWERPC_EPAPR_HCALLS_H__
+#define __POWERPC_EPAPR_HCALLS_H__
+
+#ifdef __KERNEL__
+
+/* Hypercalls use the beat ABI */
+#define KVM_HYPERCALL_BIN 0x44000022
+
+static inline long epapr_hypercall_1in_1out(unsigned int nr, unsigned long p1)
+{
+	register unsigned long hcall asm ("r11") = nr;
+	register unsigned long arg1_ret asm ("r3") = p1;
+
+	asm volatile(".long %1"
+			: "+r"(arg1_ret)
+			: "i"(KVM_HYPERCALL_BIN), "r"(hcall)
+			: "r4", "r5", "r6", "r7", "r8",
+			  "r9", "r10", "r12", "cc");
+	return arg1_ret;
+}
+
+static inline long epapr_hypercall_2in_1out(unsigned int nr,
+					unsigned long p1, unsigned long p2)
+{
+	register unsigned long hcall asm ("r11") = nr;
+	register unsigned long arg1_ret asm ("r3") = p1;
+	register unsigned long arg2 asm ("r4") = p2;
+
+	asm volatile(".long %1"
+			: "+r"(arg1_ret)
+			: "i"(KVM_HYPERCALL_BIN), "r"(hcall), "r"(arg2)
+			: "r5", "r6", "r7", "r8",
+			  "r9", "r10", "r12", "cc");
+	return arg1_ret;
+}
+
+#endif /* __KERNEL__ */
+
+#endif /* __POWERPC_EPAPR_HCALLS_H__ */