[PATCH 1/4] [HYPERCALL] Add hypercalls functions

[PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Dor Laor]

The hypercalls can be called with various parameters number.
Both x86_64 and i386 are supported.

Signed-off-by: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
---
 include/asm-i386/hypercall.h   |  142
++++++++++++++++++++++++++++++++++++++++
 include/asm-x86_64/hypercall.h |  105 +++++++++++++++++++++++++++++
 2 files changed, 247 insertions(+), 0 deletions(-)
 create mode 100644 include/asm-i386/hypercall.h
 create mode 100644 include/asm-x86_64/hypercall.h

diff --git a/include/asm-i386/hypercall.h b/include/asm-i386/hypercall.h
new file mode 100644
index 0000000..40fd31e
--- /dev/null
+++ b/include/asm-i386/hypercall.h
@@ -0,0 +1,142 @@
+#ifndef __ASM_HYPERCALL_H
+#define __ASM_HYPERCALL_H
+
+#define CONFIG_PARAVIRT 1
+#ifdef CONFIG_PARAVIRT
+
+/*
+ * Hypercalls, according to the calling convention
+ * documented in include/linux/kvm_para.h
+ *
+ * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ * Copyright (C) 2007, Qumranet, Inc., Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
See
+ * the COPYING file in the top-level directory.
+ */
+
+static inline int __hypercall0(unsigned int nr)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int __hypercall1(unsigned int nr, unsigned long p1)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr),
+		  "a" (p1)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall2(unsigned int nr, unsigned long p1, unsigned long p2)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr),
+		  "a" (p1),
+		  "c" (p2)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall3(unsigned int nr, unsigned long p1, unsigned long p2,
+	     unsigned long p3)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr),
+		  "a" (p1),
+		  "c" (p2),
+		  "d" (p3)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall4(unsigned int nr, unsigned long p1, unsigned long p2,
+	     unsigned long p3, unsigned long p4)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr),
+		  "a" (p1),
+		  "c" (p2),
+		  "d" (p3),
+		  "S" (p4)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall5(unsigned int nr, unsigned long p1, unsigned long p2,
+	     unsigned long p3, unsigned long p4, unsigned long p5)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr),
+		  "a" (p1),
+		  "c" (p2),
+		  "d" (p3),
+		  "S" (p4),
+		  "D" (p5)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall6(unsigned int nr, unsigned long p1, unsigned long p2,
+	     unsigned long p3, unsigned long p4, unsigned long p5,
+	     unsigned long p6)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "b" (nr),
+		  "a" (p1),
+		  "c" (p2),
+		  "d" (p3),
+		  "S" (p4),
+		  "D" (p5),
+		  "bp" (p6)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+#define hypercall(nr_params, args...)			\
+({							\
+	/* __ret is volatile to make sure call to this	\
+	 * function isn't optimized away by gcc. Just	\
+	 * having the __hypercallN() functions mention	\
+	 * memory is clobbered isn't enough		\
+	 */						\
+	volatile int __ret;				\
+							\
+	__ret = __hypercall##nr_params(args);		\
+							\
+	__ret;						\
+})
+
+#endif /* CONFIG_PARAVIRT */
+
+#endif	/* __ASM_HYPERCALL_H */
diff --git a/include/asm-x86_64/hypercall.h
b/include/asm-x86_64/hypercall.h
new file mode 100644
index 0000000..a331a9f
--- /dev/null
+++ b/include/asm-x86_64/hypercall.h
@@ -0,0 +1,105 @@
+#ifndef __ASM_HYPERCALL_H
+#define __ASM_HYPERCALL_H
+
+#define CONFIG_PARAVIRT 1
+#ifdef CONFIG_PARAVIRT
+
+/*
+ * Hypercalls, according to the calling convention
+ * documented in include/linux/kvm_para.h
+ *
+ * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ * Copyright (C) 2007, Qumranet, Inc., Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
See
+ * the COPYING file in the top-level directory.
+ */
+
+static inline int __hypercall0(unsigned int nr)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "a" (nr)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int __hypercall1(unsigned int nr, unsigned long p1)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "a" (nr),
+		  "D" (p1)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall2(unsigned int nr, unsigned long p1, unsigned long p2)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "a" (nr),
+		  "D" (p1),
+		  "S" (p2)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall3(unsigned int nr, unsigned long p1, unsigned long p2,
+	     unsigned long p3)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "a" (nr),
+		  "D" (p1),
+		  "S" (p2),
+		  "d" (p3)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+static inline int
+__hypercall4(unsigned int nr, unsigned long p1, unsigned long p2,
+	     unsigned long p3, unsigned long p4)
+{
+	int ret;
+	asm (" call hypercall_addr\n"
+		: "=a" (ret)
+		: "a" (nr),
+		  "D" (p1),
+		  "S" (p2),
+		  "d" (p3),
+		  "c" (p4)
+		: "memory", "cc"
+	);
+	return ret;
+}
+
+
+#define hypercall(nr_params, args...)			\
+({							\
+	/* __ret is volatile to make sure call to this	\
+	 * function isn't optimized away by gcc. Just	\
+	 * having the __hypercallN() functions mention	\
+	 * memory is clobbered isn't enough		\
+	 */						\
+	volatile int __ret;				\
+							\
+	__ret = __hypercall##nr_params(args);		\
+							\
+	__ret;						\
+})
+
+#endif /* CONFIG_PARAVIRT */
+
+#endif	/* __ASM_HYPERCALL_H */

-----
In simplicity there is elegance.
Dor Laor ;)


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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Avi Kivity]

Dor Laor wrote:
> The hypercalls can be called with various parameters number.
> Both x86_64 and i386 are supported.
>
> Signed-off-by: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
> ---
>  include/asm-i386/hypercall.h   |  142
> ++++++++++++++++++++++++++++++++++++++++
>  include/asm-x86_64/hypercall.h |  105 +++++++++++++++++++++++++++++
>  2 files changed, 247 insertions(+), 0 deletions(-)
>  create mode 100644 include/asm-i386/hypercall.h
>  create mode 100644 include/asm-x86_64/hypercall.h
>
> diff --git a/include/asm-i386/hypercall.h b/include/asm-i386/hypercall.h
> new file mode 100644
> index 0000000..40fd31e
> --- /dev/null
> +++ b/include/asm-i386/hypercall.h
> @@ -0,0 +1,142 @@
> +
> +#define CONFIG_PARAVIRT 1
>   

??

> +#ifdef CONFIG_PARAVIRT
> +
> +/*
> + * Hypercalls, according to the calling convention
> + * documented in include/linux/kvm_para.h
> + *
> + * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> + * Copyright (C) 2007, Qumranet, Inc., Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.
> See
> + * the COPYING file in the top-level directory.
> + */
> +
> +static inline int __hypercall0(unsigned int nr)
>   

These should be called __kvm_hypercallX() (and the file renamed as
well).  Linux guests support multiple hypevisors with different calling
conventions.

> +{
> +	int ret;
> +	asm (" call hypercall_addr\n"
>   

I think "asm volatile" can allow you to avoid the volatile...

> +
> +#define hypercall(nr_params, args...)			\
> +({							\
> +	/* __ret is volatile to make sure call to this	\
> +	 * function isn't optimized away by gcc. Just	\
> +	 * having the __hypercallN() functions mention	\
> +	 * memory is clobbered isn't enough		\
> +	 */						\
> +	volatile int __ret;				\
> +							\
> +	__ret = __hypercall##nr_params(args);		\
> +							\
> +	__ret;						\
> +})
>   

...here.  In fact the statement expression can go away.


-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Christian Borntraeger]

Am Samstag, 25. August 2007 schrieb Dor Laor:
> +	asm (" call hypercall_addr\n"

Hi Dor,

This cannot work, because hypercall_addr is currently not defined in todays 
kvm.git:

# grep -R hypercall_addr *
drivers/kvm/kvm.h:                unsigned char *hypercall_addr);
#

IIRC there was a definition of hypercall_addr in the older paravirt drivers 
from the rt-kernel. It seems it did not make it into this patch set.

Christian

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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Dor Laor]

>> +	asm (" call hypercall_addr\n"
>
>Hi Dor,
>
>This cannot work, because hypercall_addr is currently not defined in
>todays
>kvm.git:

The definition is inside kvm_pv.c which was in the next patchset, I'll 
join them in the next series. [Although Anthony L. has a different
method that
might catch.

>
># grep -R hypercall_addr *
>drivers/kvm/kvm.h:                unsigned char *hypercall_addr);
>#
>
>IIRC there was a definition of hypercall_addr in the older paravirt
>drivers
>from the rt-kernel. It seems it did not make it into this patch set.
>

I think the origin was the same (Ingo Molnar).

>Christian

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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Christian Borntraeger]

Am Samstag, 25. August 2007 schrieb Dor Laor:
> +static inline int
> +__hypercall2(unsigned int nr, unsigned long p1, unsigned long p2)
> +{
> +	int ret;
> +	asm (" call hypercall_addr\n"
[...]
> +	return ret;

Hello Dor,

Linux system calls return long. I think hypercalls should behave in a similar 
manner and return long as well, no?

Christian


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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Dor Laor]

>> +static inline int
>> +__hypercall2(unsigned int nr, unsigned long p1, unsigned long p2)
>> +{
>> +	int ret;
>> +	asm (" call hypercall_addr\n"
>[...]
>> +	return ret;
>
>Hello Dor,
>
>Linux system calls return long. I think hypercalls should behave in a
>similar
>manner and return long as well, no?

Logical, will be incorporated to the next patch set release.
Thanks, Dor.

>
>Christian


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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Anthony Liguori]

On Fri, 2007-08-24 at 16:57 -0700, Dor Laor wrote:
> The hypercalls can be called with various parameters number.
> Both x86_64 and i386 are supported.
> 
> Signed-off-by: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
> ---
> +static inline int
> +__hypercall6(unsigned int nr, unsigned long p1, unsigned long p2,
> +	     unsigned long p3, unsigned long p4, unsigned long p5,
> +	     unsigned long p6)
> +{
> +	int ret;
> +	asm (" call hypercall_addr\n"
> +		: "=a" (ret)
> +		: "b" (nr),
> +		  "a" (p1),
> +		  "c" (p2),
> +		  "d" (p3),
> +		  "S" (p4),
> +		  "D" (p5),
> +		  "bp" (p6)
> +		: "memory", "cc"
> +	);
> +	return ret;
> +}
> +
> +#define hypercall(nr_params, args...)			\
> +({							\
> +	/* __ret is volatile to make sure call to this	\
> +	 * function isn't optimized away by gcc. Just	\
> +	 * having the __hypercallN() functions mention	\
> +	 * memory is clobbered isn't enough		\
> +	 */						\
> +	volatile int __ret;				\
> +							\
> +	__ret = __hypercall##nr_params(args);		\
> +							\
> +	__ret;						\
> +})

A couple things are different in my patchset.  I didn't do this
hypercall macro.  I tried it at first but IMHO it was pretty ugly.  It
makes things less readable to me.  The second thing is I only have up to
4 parameters to a hypercall.  That leaves some GP registers on 32-bit
and Xen seems to be happily using 4 registers so I don't think there's
anything we can't express without the extra 2.

Regards,

Anthony Liguori


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Re: [PATCH 1/4] [HYPERCALL] Add hypercalls functions

[Dor Laor]

>> The hypercalls can be called with various parameters number.
>> Both x86_64 and i386 are supported.
>>
>> Signed-off-by: Dor Laor <dor.laor-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
>> ---
>> +static inline int
>> +__hypercall6(unsigned int nr, unsigned long p1, unsigned long p2,
>> +	     unsigned long p3, unsigned long p4, unsigned long p5,
>> +	     unsigned long p6)
>> +{
>> +	int ret;
>> +	asm (" call hypercall_addr\n"
>> +		: "=a" (ret)
>> +		: "b" (nr),
>> +		  "a" (p1),
>> +		  "c" (p2),
>> +		  "d" (p3),
>> +		  "S" (p4),
>> +		  "D" (p5),
>> +		  "bp" (p6)
>> +		: "memory", "cc"
>> +	);
>> +	return ret;
>> +}
>> +
>> +#define hypercall(nr_params, args...)			\
>> +({							\
>> +	/* __ret is volatile to make sure call to this	\
>> +	 * function isn't optimized away by gcc. Just	\
>> +	 * having the __hypercallN() functions mention	\
>> +	 * memory is clobbered isn't enough		\
>> +	 */						\
>> +	volatile int __ret;				\
>> +							\
>> +	__ret = __hypercall##nr_params(args);		\
>> +							\
>> +	__ret;						\
>> +})
>
>A couple things are different in my patchset.  I didn't do this
>hypercall macro.  I tried it at first but IMHO it was pretty ugly.  It

It will also simplify the call to the hypercall, instead of
hypercall(X,TYPE,...) hypercallX(Type,...)
Will be changed in the next drop.

>makes things less readable to me.  The second thing is I only have up
to
>4 parameters to a hypercall.  That leaves some GP registers on 32-bit
>and Xen seems to be happily using 4 registers so I don't think there's
>anything we can't express without the extra 2.
>

Agreed, actually the x86_64 has only 4 parameters too.
Thanks,
Dor.

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