[kvm-unit-tests,v3,2/3] s390x: define UV compatible I/O allocation

Commit Message

Pierre Morel Jan. 19, 2021, 7:52 p.m. UTC

To centralize the memory allocation for I/O we define
the alloc_io_page/free_io_page functions which share the I/O
memory with the host in case the guest runs with
protected virtualization.

Signed-off-by: Pierre Morel <[e-mail]>
---
 lib/s390x/malloc_io.c | 50 +++++++++++++++++++++++++++++++++++++++++++
 lib/s390x/malloc_io.h | 18 ++++++++++++++++
 s390x/Makefile        |  1 +
 3 files changed, 69 insertions(+)
 create mode 100644 lib/s390x/malloc_io.c
 create mode 100644 lib/s390x/malloc_io.h

Comments

Thomas Huth Jan. 20, 2021, 11:01 a.m. UTC | #1

On 19/01/2021 20.52, Pierre Morel wrote:
> To centralize the memory allocation for I/O we define
> the alloc_io_page/free_io_page functions which share the I/O
> memory with the host in case the guest runs with
> protected virtualization.
> 
> Signed-off-by: Pierre Morel <[e-mail]>
> ---
>   lib/s390x/malloc_io.c | 50 +++++++++++++++++++++++++++++++++++++++++++
>   lib/s390x/malloc_io.h | 18 ++++++++++++++++
>   s390x/Makefile        |  1 +
>   3 files changed, 69 insertions(+)
>   create mode 100644 lib/s390x/malloc_io.c
>   create mode 100644 lib/s390x/malloc_io.h
> 
> diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
> new file mode 100644
> index 0000000..2a946e0
> --- /dev/null
> +++ b/lib/s390x/malloc_io.c
> @@ -0,0 +1,50 @@
> +/*
> + * I/O page allocation
> + *
> + * Copyright (c) 2021 IBM Corp
> + *
> + * Authors:
> + *  Pierre Morel <[e-mail]>
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2.

Janosch recently started to introduce SPDX identifieres to the s390x code, 
so I think it would be good to use them here, too.

> + * Using this interface provide host access to the allocated pages in
> + * case the guest is a secure guest.
> + * This is needed for I/O buffers.
> + *
> + */
> +#include <libcflat.h>
> +#include <asm/page.h>
> +#include <asm/uv.h>
> +#include <malloc_io.h>
> +#include <alloc_page.h>
> +#include <asm/facility.h>
> +
> +void *alloc_io_page(int size)
> +{
> +	void *p;
> +
> +	assert(size <= PAGE_SIZE);

Apart from the assert() statement, the size parameter seems to be completely 
unused. It's also weird to have the function named alloc_something_page() 
and then have a parameter that takes bytes. Thus I'd suggest to either drop 
the size parameter completely, or to rename the function to alloc_io_mem and 
then to alloc multiple pages below in case the size is bigger than 
PAGE_SIZE. Or maybe even to name the function alloc_io_pages and then use 
"int num_pages" as a parameter, allowing to allocate multiple pages at once?

> +
> +	p = alloc_pages_flags(1, AREA_DMA31);
> +	if (!p)
> +		return NULL;
> +	memset(p, 0, PAGE_SIZE);
> +
> +	if (!test_facility(158))
> +		return p;
> +
> +	if (uv_set_shared((unsigned long)p) == 0)
> +		return p;
> +
> +	free_pages(p);
> +	return NULL;
> +}
> +
> +void free_io_page(void *p)
> +{
> +	if (test_facility(158))
> +		uv_remove_shared((unsigned long)p);
> +	free_pages(p);
> +}
> diff --git a/lib/s390x/malloc_io.h b/lib/s390x/malloc_io.h
> new file mode 100644
> index 0000000..f780191
> --- /dev/null
> +++ b/lib/s390x/malloc_io.h
> @@ -0,0 +1,18 @@
> +/*
> + * I/O allocations
> + *
> + * Copyright (c) 2021 IBM Corp
> + *
> + * Authors:
> + *  Pierre Morel <[e-mail]>
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2.
> + */
Please also add SPDX license information here.

  Thomas

Claudio Imbrenda Jan. 20, 2021, 12:25 p.m. UTC | #2

On Tue, 19 Jan 2021 20:52:23 +0100
Pierre Morel <[e-mail]> wrote:

> To centralize the memory allocation for I/O we define
> the alloc_io_page/free_io_page functions which share the I/O
> memory with the host in case the guest runs with
> protected virtualization.
> 
> Signed-off-by: Pierre Morel <[e-mail]>
> ---
>  lib/s390x/malloc_io.c | 50
> +++++++++++++++++++++++++++++++++++++++++++ lib/s390x/malloc_io.h |
> 18 ++++++++++++++++ s390x/Makefile        |  1 +
>  3 files changed, 69 insertions(+)
>  create mode 100644 lib/s390x/malloc_io.c
>  create mode 100644 lib/s390x/malloc_io.h
> 
> diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
> new file mode 100644
> index 0000000..2a946e0
> --- /dev/null
> +++ b/lib/s390x/malloc_io.c
> @@ -0,0 +1,50 @@
> +/*
> + * I/O page allocation
> + *
> + * Copyright (c) 2021 IBM Corp
> + *
> + * Authors:
> + *  Pierre Morel <[e-mail]>
> + *
> + * This code is free software; you can redistribute it and/or modify
> it
> + * under the terms of the GNU General Public License version 2.
> + *
> + * Using this interface provide host access to the allocated pages in
> + * case the guest is a secure guest.
> + * This is needed for I/O buffers.
> + *
> + */
> +#include <libcflat.h>
> +#include <asm/page.h>
> +#include <asm/uv.h>
> +#include <malloc_io.h>
> +#include <alloc_page.h>
> +#include <asm/facility.h>
> +
> +void *alloc_io_page(int size)
> +{
> +	void *p;
> +
> +	assert(size <= PAGE_SIZE);

I agree with Thomas here, remove size, or use it as a page count or
page order.

> +	p = alloc_pages_flags(1, AREA_DMA31);

you are allocating 2 pages here...

> +	if (!p)
> +		return NULL;
> +	memset(p, 0, PAGE_SIZE);

...and then clearing only one

but since you did not specify FLAG_DONTZERO, the page has been cleared
already by the allocator

> +
> +	if (!test_facility(158))
> +		return p;
> +
> +	if (uv_set_shared((unsigned long)p) == 0)
> +		return p;
> +
> +	free_pages(p);
> +	return NULL;
> +}
> +
> +void free_io_page(void *p)
> +{
> +	if (test_facility(158))
> +		uv_remove_shared((unsigned long)p);
> +	free_pages(p);
> +}
> diff --git a/lib/s390x/malloc_io.h b/lib/s390x/malloc_io.h
> new file mode 100644
> index 0000000..f780191
> --- /dev/null
> +++ b/lib/s390x/malloc_io.h
> @@ -0,0 +1,18 @@
> +/*
> + * I/O allocations
> + *
> + * Copyright (c) 2021 IBM Corp
> + *
> + * Authors:
> + *  Pierre Morel <[e-mail]>
> + *
> + * This code is free software; you can redistribute it and/or modify
> it
> + * under the terms of the GNU General Public License version 2.
> + */
> +#ifndef _S390X_MALLOC_IO_H_
> +#define _S390X_MALLOC_IO_H_
> +
> +void *alloc_io_page(int size);
> +void free_io_page(void *p);
> +
> +#endif /* _S390X_MALLOC_IO_H_ */
> diff --git a/s390x/Makefile b/s390x/Makefile
> index b079a26..4b6301c 100644
> --- a/s390x/Makefile
> +++ b/s390x/Makefile
> @@ -63,6 +63,7 @@ cflatobjs += lib/s390x/smp.o
>  cflatobjs += lib/s390x/vm.o
>  cflatobjs += lib/s390x/css_dump.o
>  cflatobjs += lib/s390x/css_lib.o
> +cflatobjs += lib/s390x/malloc_io.o
>  
>  OBJDIRS += lib/s390x
>

Pierre Morel Jan. 20, 2021, 12:39 p.m. UTC | #3

On 1/20/21 12:01 PM, Thomas Huth wrote:
> On 19/01/2021 20.52, Pierre Morel wrote:
>> To centralize the memory allocation for I/O we define
>> the alloc_io_page/free_io_page functions which share the I/O
>> memory with the host in case the guest runs with
>> protected virtualization.
>>
>> Signed-off-by: Pierre Morel <[e-mail]>
>> ---
>>   lib/s390x/malloc_io.c | 50 +++++++++++++++++++++++++++++++++++++++++++
>>   lib/s390x/malloc_io.h | 18 ++++++++++++++++
>>   s390x/Makefile        |  1 +
>>   3 files changed, 69 insertions(+)
>>   create mode 100644 lib/s390x/malloc_io.c
>>   create mode 100644 lib/s390x/malloc_io.h
>>
>> diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
>> new file mode 100644
>> index 0000000..2a946e0
>> --- /dev/null
>> +++ b/lib/s390x/malloc_io.c
>> @@ -0,0 +1,50 @@
>> +/*
>> + * I/O page allocation
>> + *
>> + * Copyright (c) 2021 IBM Corp
>> + *
>> + * Authors:
>> + *  Pierre Morel <[e-mail]>
>> + *
>> + * This code is free software; you can redistribute it and/or modify it
>> + * under the terms of the GNU General Public License version 2.
> 
> Janosch recently started to introduce SPDX identifieres to the s390x 
> code, so I think it would be good to use them here, too.
> 
>> + * Using this interface provide host access to the allocated pages in
>> + * case the guest is a secure guest.
>> + * This is needed for I/O buffers.
>> + *
>> + */
>> +#include <libcflat.h>
>> +#include <asm/page.h>
>> +#include <asm/uv.h>
>> +#include <malloc_io.h>
>> +#include <alloc_page.h>
>> +#include <asm/facility.h>
>> +
>> +void *alloc_io_page(int size)
>> +{
>> +    void *p;
>> +
>> +    assert(size <= PAGE_SIZE);
> 
> Apart from the assert() statement, the size parameter seems to be 
> completely unused. It's also weird to have the function named 

right.

> alloc_something_page() and then have a parameter that takes bytes. Thus 
> I'd suggest to either drop the size parameter completely, or to rename 
> the function to alloc_io_mem and then to alloc multiple pages below in 
> case the size is bigger than PAGE_SIZE. Or maybe even to name the 
> function alloc_io_pages and then use "int num_pages" as a parameter, 
> allowing to allocate multiple pages at once?

OK, may bet using order as with the alloc_pages_flags would be fine.
Then I will need a new flag in the pages.

> 
>> +
>> +    p = alloc_pages_flags(1, AREA_DMA31);

humm 0 here (Claudio)

>> +    if (!p)
>> +        return NULL;
>> +    memset(p, 0, PAGE_SIZE);
>> +
>> +    if (!test_facility(158))
>> +        return p;
>> +
>> +    if (uv_set_shared((unsigned long)p) == 0)
>> +        return p;
>> +
>> +    free_pages(p);
>> +    return NULL;
>> +}
>> +
>> +void free_io_page(void *p)
>> +{
>> +    if (test_facility(158))
>> +        uv_remove_shared((unsigned long)p);
>> +    free_pages(p);
>> +}
>> diff --git a/lib/s390x/malloc_io.h b/lib/s390x/malloc_io.h
>> new file mode 100644
>> index 0000000..f780191
>> --- /dev/null
>> +++ b/lib/s390x/malloc_io.h
>> @@ -0,0 +1,18 @@
>> +/*
>> + * I/O allocations
>> + *
>> + * Copyright (c) 2021 IBM Corp
>> + *
>> + * Authors:
>> + *  Pierre Morel <[e-mail]>
>> + *
>> + * This code is free software; you can redistribute it and/or modify it
>> + * under the terms of the GNU General Public License version 2.
>> + */
> Please also add SPDX license information here.

Will do.

Thanks for reviewing,
Pierre

> 
>   Thomas
>

Pierre Morel Jan. 20, 2021, 12:41 p.m. UTC | #4

On 1/20/21 1:25 PM, Claudio Imbrenda wrote:
> On Tue, 19 Jan 2021 20:52:23 +0100
> Pierre Morel <[e-mail]> wrote:
> 
>> To centralize the memory allocation for I/O we define
>> the alloc_io_page/free_io_page functions which share the I/O
>> memory with the host in case the guest runs with
>> protected virtualization.
>>
>> Signed-off-by: Pierre Morel <[e-mail]>
>> ---
>>   lib/s390x/malloc_io.c | 50
>> +++++++++++++++++++++++++++++++++++++++++++ lib/s390x/malloc_io.h |
>> 18 ++++++++++++++++ s390x/Makefile        |  1 +
>>   3 files changed, 69 insertions(+)
>>   create mode 100644 lib/s390x/malloc_io.c
>>   create mode 100644 lib/s390x/malloc_io.h
>>
>> diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
>> new file mode 100644
>> index 0000000..2a946e0
>> --- /dev/null
>> +++ b/lib/s390x/malloc_io.c
>> @@ -0,0 +1,50 @@
>> +/*
>> + * I/O page allocation
>> + *
>> + * Copyright (c) 2021 IBM Corp
>> + *
>> + * Authors:
>> + *  Pierre Morel <[e-mail]>
>> + *
>> + * This code is free software; you can redistribute it and/or modify
>> it
>> + * under the terms of the GNU General Public License version 2.
>> + *
>> + * Using this interface provide host access to the allocated pages in
>> + * case the guest is a secure guest.
>> + * This is needed for I/O buffers.
>> + *
>> + */
>> +#include <libcflat.h>
>> +#include <asm/page.h>
>> +#include <asm/uv.h>
>> +#include <malloc_io.h>
>> +#include <alloc_page.h>
>> +#include <asm/facility.h>
>> +
>> +void *alloc_io_page(int size)
>> +{
>> +	void *p;
>> +
>> +	assert(size <= PAGE_SIZE);
> 
> I agree with Thomas here, remove size, or use it as a page count or
> page order.
> 
>> +	p = alloc_pages_flags(1, AREA_DMA31);
> 
> you are allocating 2 pages here...

humm, yes, forgot to change this as I changed to your interface.

Thanks for the reviewing,
Pierre

Patch

diff --git a/lib/s390x/malloc_io.c b/lib/s390x/malloc_io.c
new file mode 100644
index 0000000..2a946e0
--- /dev/null
+++ b/lib/s390x/malloc_io.c
@@ -0,0 +1,50 @@ 
+/*
+ * I/O page allocation
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ *  Pierre Morel <[e-mail]>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2.
+ *
+ * Using this interface provide host access to the allocated pages in
+ * case the guest is a secure guest.
+ * This is needed for I/O buffers.
+ *
+ */
+#include <libcflat.h>
+#include <asm/page.h>
+#include <asm/uv.h>
+#include <malloc_io.h>
+#include <alloc_page.h>
+#include <asm/facility.h>
+
+void *alloc_io_page(int size)
+{
+	void *p;
+
+	assert(size <= PAGE_SIZE);
+
+	p = alloc_pages_flags(1, AREA_DMA31);
+	if (!p)
+		return NULL;
+	memset(p, 0, PAGE_SIZE);
+
+	if (!test_facility(158))
+		return p;
+
+	if (uv_set_shared((unsigned long)p) == 0)
+		return p;
+
+	free_pages(p);
+	return NULL;
+}
+
+void free_io_page(void *p)
+{
+	if (test_facility(158))
+		uv_remove_shared((unsigned long)p);
+	free_pages(p);
+}
diff --git a/lib/s390x/malloc_io.h b/lib/s390x/malloc_io.h
new file mode 100644
index 0000000..f780191
--- /dev/null
+++ b/lib/s390x/malloc_io.h
@@ -0,0 +1,18 @@ 
+/*
+ * I/O allocations
+ *
+ * Copyright (c) 2021 IBM Corp
+ *
+ * Authors:
+ *  Pierre Morel <[e-mail]>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2.
+ */
+#ifndef _S390X_MALLOC_IO_H_
+#define _S390X_MALLOC_IO_H_
+
+void *alloc_io_page(int size);
+void free_io_page(void *p);
+
+#endif /* _S390X_MALLOC_IO_H_ */
diff --git a/s390x/Makefile b/s390x/Makefile
index b079a26..4b6301c 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -63,6 +63,7 @@  cflatobjs += lib/s390x/smp.o
 cflatobjs += lib/s390x/vm.o
 cflatobjs += lib/s390x/css_dump.o
 cflatobjs += lib/s390x/css_lib.o
+cflatobjs += lib/s390x/malloc_io.o
 
 OBJDIRS += lib/s390x