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* Creating 'wic' image
From: Mike Looijmans @ 2016-11-14 15:23 UTC (permalink / raw)
  To: OE-core

In order to make life easier for people, I was looking into creating images 
with the "wic" tool.

There's just one big piece of documentation lacking: What's the format it 
wants my rootfs and boot files?
http://www.yoctoproject.org/docs/2.2/mega-manual/mega-manual.html

Basically I want an SD card with a FAT boot partition and an ext4 rootfs, and 
"sdimage-bootpart" is pretty close to that.

Without "wic", I build a tar of the rootfs and copy the boot files using a bit 
of shell scripting.

Adding "wic" to IMAGE_FSTYPES just results in an error that I should set 
WKS_FILE but I have no clue as to what file that should point to.

Running wic manually just results in more missing variables that I can't find 
what to specify in them...


Kind regards,

Mike Looijmans
System Expert

TOPIC Products
Materiaalweg 4, NL-5681 RJ Best
Postbus 440, NL-5680 AK Best
Telefoon: +31 (0) 499 33 69 79
E-mail: mike.looijmans@topicproducts.com
Website: www.topicproducts.com

Please consider the environment before printing this e-mail







^ permalink raw reply

* Re: [PATCH 4/4] sanity.bbclass: fix check_connectivity() for BB_NO_NETWORK = "0"
From: Christopher Larson @ 2016-11-14 15:38 UTC (permalink / raw)
  To: Robert Yang; +Cc: Patches and discussions about the oe-core layer
In-Reply-To: <ea0d4ea9-f9c6-64bf-2647-bd1f55b62534@windriver.com>

[-- Attachment #1: Type: text/plain, Size: 2233 bytes --]

On Mon, Nov 14, 2016 at 8:37 AM, Robert Yang <liezhi.yang@windriver.com>
wrote:

> On 11/14/2016 11:03 PM, Christopher Larson wrote:
>
>>
>> On Mon, Nov 14, 2016 at 7:34 AM, Robert Yang <liezhi.yang@windriver.com
>> <mailto:liezhi.yang@windriver.com>> wrote:
>>
>>     The old code:
>>     network_enabled = not d.getVar('BB_NO_NETWORK', True)
>>
>>     It is True only when BB_NO_NETWORK is not set (None),
>>     but BB_NO_NETWORK = "0" should also be True while "1" means no
>> network,
>>     "0" means need network in a normal case.
>>
>>     Signed-off-by: Robert Yang <liezhi.yang@windriver.com
>>     <mailto:liezhi.yang@windriver.com>>
>>     ---
>>      meta/classes/sanity.bbclass | 14 +++++++++-----
>>      1 file changed, 9 insertions(+), 5 deletions(-)
>>
>>     diff --git a/meta/classes/sanity.bbclass b/meta/classes/sanity.bbclass
>>     index 7e383f9..c5e3809 100644
>>     --- a/meta/classes/sanity.bbclass
>>     +++ b/meta/classes/sanity.bbclass
>>     @@ -363,15 +363,19 @@ def check_connectivity(d):
>>          test_uris = (d.getVar('CONNECTIVITY_CHECK_URIS', True) or
>> "").split()
>>          retval = ""
>>
>>     +    bbn = d.getVar('BB_NO_NETWORK', True)
>>     +    if bbn not in (None, '0', '1'):
>>     +        return 'BB_NO_NETWORK should be "0" or "1", but it is "%s"'
>> % bbn
>>
>>
>> Does this mirror the same logic used in bitbake? What’s the behavior if
>> it’s
>> set, but to the empty string?
>>
>
> bitbake only checks whether it equals "1" or not. Without this patch, an
> empty
> string is the same as not set since it doesn't equal to "1". But if it is
> set to "0", bitbake uses it as enable network, sanity.bbclass uses it
> as disable netowrk, which are conflicted. We can add checking for empty
> string,
> but do we have to ? Limit it to "0" or "1" makes things clear.


IMO if we’re going to change the semantics, we should do it in bitbake and
then mirror that in the metadata. Sanity checking should mirror the actual
variable behavior where it’s used.
-- 
Christopher Larson
clarson at kergoth dot com
Founder - BitBake, OpenEmbedded, OpenZaurus
Maintainer - Tslib
Senior Software Engineer, Mentor Graphics

[-- Attachment #2: Type: text/html, Size: 3362 bytes --]

^ permalink raw reply

* Re: [RFCv2 PATCH 2/5] drm/bridge: dw_hdmi: remove CEC engine register definitions
From: Russell King - ARM Linux @ 2016-11-14 15:39 UTC (permalink / raw)
  To: Hans Verkuil; +Cc: linux-media, linux-arm-kernel, linux-fbdev, dri-devel
In-Reply-To: <1479136968-24477-3-git-send-email-hverkuil@xs4all.nl>

I can't comment on these, you've not included me in patch 1 nor the
covering message.

On Mon, Nov 14, 2016 at 04:22:45PM +0100, Hans Verkuil wrote:
> From: Russell King <rmk+kernel@arm.linux.org.uk>
> 
> We don't need the CEC engine register definitions, so let's remove them.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
>  drivers/gpu/drm/bridge/dw-hdmi.h | 45 ----------------------------------------
>  1 file changed, 45 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.h b/drivers/gpu/drm/bridge/dw-hdmi.h
> index fc9a560..26d6845 100644
> --- a/drivers/gpu/drm/bridge/dw-hdmi.h
> +++ b/drivers/gpu/drm/bridge/dw-hdmi.h
> @@ -478,51 +478,6 @@
>  #define HDMI_A_PRESETUP                         0x501A
>  #define HDMI_A_SRM_BASE                         0x5020
>  
> -/* CEC Engine Registers */
> -#define HDMI_CEC_CTRL                           0x7D00
> -#define HDMI_CEC_STAT                           0x7D01
> -#define HDMI_CEC_MASK                           0x7D02
> -#define HDMI_CEC_POLARITY                       0x7D03
> -#define HDMI_CEC_INT                            0x7D04
> -#define HDMI_CEC_ADDR_L                         0x7D05
> -#define HDMI_CEC_ADDR_H                         0x7D06
> -#define HDMI_CEC_TX_CNT                         0x7D07
> -#define HDMI_CEC_RX_CNT                         0x7D08
> -#define HDMI_CEC_TX_DATA0                       0x7D10
> -#define HDMI_CEC_TX_DATA1                       0x7D11
> -#define HDMI_CEC_TX_DATA2                       0x7D12
> -#define HDMI_CEC_TX_DATA3                       0x7D13
> -#define HDMI_CEC_TX_DATA4                       0x7D14
> -#define HDMI_CEC_TX_DATA5                       0x7D15
> -#define HDMI_CEC_TX_DATA6                       0x7D16
> -#define HDMI_CEC_TX_DATA7                       0x7D17
> -#define HDMI_CEC_TX_DATA8                       0x7D18
> -#define HDMI_CEC_TX_DATA9                       0x7D19
> -#define HDMI_CEC_TX_DATA10                      0x7D1a
> -#define HDMI_CEC_TX_DATA11                      0x7D1b
> -#define HDMI_CEC_TX_DATA12                      0x7D1c
> -#define HDMI_CEC_TX_DATA13                      0x7D1d
> -#define HDMI_CEC_TX_DATA14                      0x7D1e
> -#define HDMI_CEC_TX_DATA15                      0x7D1f
> -#define HDMI_CEC_RX_DATA0                       0x7D20
> -#define HDMI_CEC_RX_DATA1                       0x7D21
> -#define HDMI_CEC_RX_DATA2                       0x7D22
> -#define HDMI_CEC_RX_DATA3                       0x7D23
> -#define HDMI_CEC_RX_DATA4                       0x7D24
> -#define HDMI_CEC_RX_DATA5                       0x7D25
> -#define HDMI_CEC_RX_DATA6                       0x7D26
> -#define HDMI_CEC_RX_DATA7                       0x7D27
> -#define HDMI_CEC_RX_DATA8                       0x7D28
> -#define HDMI_CEC_RX_DATA9                       0x7D29
> -#define HDMI_CEC_RX_DATA10                      0x7D2a
> -#define HDMI_CEC_RX_DATA11                      0x7D2b
> -#define HDMI_CEC_RX_DATA12                      0x7D2c
> -#define HDMI_CEC_RX_DATA13                      0x7D2d
> -#define HDMI_CEC_RX_DATA14                      0x7D2e
> -#define HDMI_CEC_RX_DATA15                      0x7D2f
> -#define HDMI_CEC_LOCK                           0x7D30
> -#define HDMI_CEC_WKUPCTRL                       0x7D31
> -
>  /* I2C Master Registers (E-DDC) */
>  #define HDMI_I2CM_SLAVE                         0x7E00
>  #define HDMI_I2CM_ADDRESS                       0x7E01
> -- 
> 2.8.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

^ permalink raw reply

* [RFCv2 PATCH 2/5] drm/bridge: dw_hdmi: remove CEC engine register definitions
From: Russell King - ARM Linux @ 2016-11-14 15:39 UTC (permalink / raw)
  To: linux-arm-kernel
In-Reply-To: <1479136968-24477-3-git-send-email-hverkuil@xs4all.nl>

I can't comment on these, you've not included me in patch 1 nor the
covering message.

On Mon, Nov 14, 2016 at 04:22:45PM +0100, Hans Verkuil wrote:
> From: Russell King <rmk+kernel@arm.linux.org.uk>
> 
> We don't need the CEC engine register definitions, so let's remove them.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
>  drivers/gpu/drm/bridge/dw-hdmi.h | 45 ----------------------------------------
>  1 file changed, 45 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.h b/drivers/gpu/drm/bridge/dw-hdmi.h
> index fc9a560..26d6845 100644
> --- a/drivers/gpu/drm/bridge/dw-hdmi.h
> +++ b/drivers/gpu/drm/bridge/dw-hdmi.h
> @@ -478,51 +478,6 @@
>  #define HDMI_A_PRESETUP                         0x501A
>  #define HDMI_A_SRM_BASE                         0x5020
>  
> -/* CEC Engine Registers */
> -#define HDMI_CEC_CTRL                           0x7D00
> -#define HDMI_CEC_STAT                           0x7D01
> -#define HDMI_CEC_MASK                           0x7D02
> -#define HDMI_CEC_POLARITY                       0x7D03
> -#define HDMI_CEC_INT                            0x7D04
> -#define HDMI_CEC_ADDR_L                         0x7D05
> -#define HDMI_CEC_ADDR_H                         0x7D06
> -#define HDMI_CEC_TX_CNT                         0x7D07
> -#define HDMI_CEC_RX_CNT                         0x7D08
> -#define HDMI_CEC_TX_DATA0                       0x7D10
> -#define HDMI_CEC_TX_DATA1                       0x7D11
> -#define HDMI_CEC_TX_DATA2                       0x7D12
> -#define HDMI_CEC_TX_DATA3                       0x7D13
> -#define HDMI_CEC_TX_DATA4                       0x7D14
> -#define HDMI_CEC_TX_DATA5                       0x7D15
> -#define HDMI_CEC_TX_DATA6                       0x7D16
> -#define HDMI_CEC_TX_DATA7                       0x7D17
> -#define HDMI_CEC_TX_DATA8                       0x7D18
> -#define HDMI_CEC_TX_DATA9                       0x7D19
> -#define HDMI_CEC_TX_DATA10                      0x7D1a
> -#define HDMI_CEC_TX_DATA11                      0x7D1b
> -#define HDMI_CEC_TX_DATA12                      0x7D1c
> -#define HDMI_CEC_TX_DATA13                      0x7D1d
> -#define HDMI_CEC_TX_DATA14                      0x7D1e
> -#define HDMI_CEC_TX_DATA15                      0x7D1f
> -#define HDMI_CEC_RX_DATA0                       0x7D20
> -#define HDMI_CEC_RX_DATA1                       0x7D21
> -#define HDMI_CEC_RX_DATA2                       0x7D22
> -#define HDMI_CEC_RX_DATA3                       0x7D23
> -#define HDMI_CEC_RX_DATA4                       0x7D24
> -#define HDMI_CEC_RX_DATA5                       0x7D25
> -#define HDMI_CEC_RX_DATA6                       0x7D26
> -#define HDMI_CEC_RX_DATA7                       0x7D27
> -#define HDMI_CEC_RX_DATA8                       0x7D28
> -#define HDMI_CEC_RX_DATA9                       0x7D29
> -#define HDMI_CEC_RX_DATA10                      0x7D2a
> -#define HDMI_CEC_RX_DATA11                      0x7D2b
> -#define HDMI_CEC_RX_DATA12                      0x7D2c
> -#define HDMI_CEC_RX_DATA13                      0x7D2d
> -#define HDMI_CEC_RX_DATA14                      0x7D2e
> -#define HDMI_CEC_RX_DATA15                      0x7D2f
> -#define HDMI_CEC_LOCK                           0x7D30
> -#define HDMI_CEC_WKUPCTRL                       0x7D31
> -
>  /* I2C Master Registers (E-DDC) */
>  #define HDMI_I2CM_SLAVE                         0x7E00
>  #define HDMI_I2CM_ADDRESS                       0x7E01
> -- 
> 2.8.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

^ permalink raw reply

* [PATCH] ARM: ftrace: fix syscall name matching
From: Steven Rostedt @ 2016-11-14 15:40 UTC (permalink / raw)
  To: linux-arm-kernel
In-Reply-To: <20161114134017.GJ1041@n2100.armlinux.org.uk>

On Mon, 14 Nov 2016 13:40:17 +0000
Russell King - ARM Linux <linux@armlinux.org.uk> wrote:

> On Mon, Nov 14, 2016 at 02:03:45PM +0100, Rabin Vincent wrote:
> > From: Rabin Vincent <rabinv@axis.com>
> > 
> > ARM has a few system calls (most notably mmap) for which the names of
> > the functions which are referenced in the syscall table do not match the
> > names of the syscall tracepoints.  As a consequence of this, these
> > tracepoints are not made available.  Implement
> > arch_syscall_match_sym_name to fix this and allow tracing even these
> > system calls.
> > 
> > Signed-off-by: Rabin Vincent <rabinv@axis.com>
> > ---
> >  arch/arm/include/asm/ftrace.h | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
> > index bfe2a2f..8467909 100644
> > --- a/arch/arm/include/asm/ftrace.h
> > +++ b/arch/arm/include/asm/ftrace.h
> > @@ -54,6 +54,27 @@ static inline void *return_address(unsigned int level)
> >  
> >  #define ftrace_return_address(n) return_address(n)
> >  
> > +#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
> > +
> > +static inline bool arch_syscall_match_sym_name(const char *sym,
> > +					       const char *name)
> > +{
> > +	/* Skip sys_ */
> > +	sym += 4;
> > +	name += 4;  
> 
> Is this really safe?  What guarantees that we can wind forward four
> bytes here?  If it's always safe, it needs a better comment than just
> two words.

I believe it is, but a comment would do well.

The "sym" comes from kallsyms_lookup(syscall-address...)

Which it becomes the syscall function. Mostly defined by:

 include/linux/syscalls.h:

#define SYSCALL_DEFINEx(x, name)
	asmlinkage long sys_##name(...)

But there are cases that archs can define their own system calls
outside of this method. But then again, those system calls wont have
tracepoints attached to them, and they wont be called with this
function.

The "name" part comes from the system call tracepoint.

#define SYSCALL_METADATA(sname, ...)
	static struct syscall_metadata
	  __syscall_meta_##sname = {
		.name		= "sys"#sname,


It too appends the "sys" to the name. Note, sname here is called with
appending "_" to name, so the .name will start with "sys_" as well.

I'm guessing that there's an issue if more than one function name is
used for the same function, that is, the symbol maps to the same IP.
Then kallsyms_lookup() can return different function names for the same
function being called, and I'm guessing that's what this is trying to
fix.

-- Steve

> 
> > +
> > +	if (!strcmp(sym, "mmap2"))
> > +		sym = "mmap_pgoff";
> > +	else if (!strcmp(sym, "statfs64_wrapper"))
> > +		sym = "statfs64";
> > +	else if (!strcmp(sym, "fstatfs64_wrapper"))
> > +		sym = "fstatfs64";
> > +	else if (!strcmp(sym, "arm_fadvise64_64"))
> > +		sym = "fadvise64_64";
> > +
> > +	return !strcmp(sym, name);
> > +}
> > +
> >  #endif /* ifndef __ASSEMBLY__ */
> >  
> >  #endif /* _ASM_ARM_FTRACE */
> > -- 
> > 2.1.4
> >   
> 

^ permalink raw reply

* Re: [PATCH] ARM: ftrace: fix syscall name matching
From: Steven Rostedt @ 2016-11-14 15:40 UTC (permalink / raw)
  To: Russell King - ARM Linux
  Cc: Rabin Vincent, linux-arm-kernel, linux-kernel, Rabin Vincent
In-Reply-To: <20161114134017.GJ1041@n2100.armlinux.org.uk>

On Mon, 14 Nov 2016 13:40:17 +0000
Russell King - ARM Linux <linux@armlinux.org.uk> wrote:

> On Mon, Nov 14, 2016 at 02:03:45PM +0100, Rabin Vincent wrote:
> > From: Rabin Vincent <rabinv@axis.com>
> > 
> > ARM has a few system calls (most notably mmap) for which the names of
> > the functions which are referenced in the syscall table do not match the
> > names of the syscall tracepoints.  As a consequence of this, these
> > tracepoints are not made available.  Implement
> > arch_syscall_match_sym_name to fix this and allow tracing even these
> > system calls.
> > 
> > Signed-off-by: Rabin Vincent <rabinv@axis.com>
> > ---
> >  arch/arm/include/asm/ftrace.h | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
> > index bfe2a2f..8467909 100644
> > --- a/arch/arm/include/asm/ftrace.h
> > +++ b/arch/arm/include/asm/ftrace.h
> > @@ -54,6 +54,27 @@ static inline void *return_address(unsigned int level)
> >  
> >  #define ftrace_return_address(n) return_address(n)
> >  
> > +#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
> > +
> > +static inline bool arch_syscall_match_sym_name(const char *sym,
> > +					       const char *name)
> > +{
> > +	/* Skip sys_ */
> > +	sym += 4;
> > +	name += 4;  
> 
> Is this really safe?  What guarantees that we can wind forward four
> bytes here?  If it's always safe, it needs a better comment than just
> two words.

I believe it is, but a comment would do well.

The "sym" comes from kallsyms_lookup(syscall-address...)

Which it becomes the syscall function. Mostly defined by:

 include/linux/syscalls.h:

#define SYSCALL_DEFINEx(x, name)
	asmlinkage long sys_##name(...)

But there are cases that archs can define their own system calls
outside of this method. But then again, those system calls wont have
tracepoints attached to them, and they wont be called with this
function.

The "name" part comes from the system call tracepoint.

#define SYSCALL_METADATA(sname, ...)
	static struct syscall_metadata
	  __syscall_meta_##sname = {
		.name		= "sys"#sname,


It too appends the "sys" to the name. Note, sname here is called with
appending "_" to name, so the .name will start with "sys_" as well.

I'm guessing that there's an issue if more than one function name is
used for the same function, that is, the symbol maps to the same IP.
Then kallsyms_lookup() can return different function names for the same
function being called, and I'm guessing that's what this is trying to
fix.

-- Steve

> 
> > +
> > +	if (!strcmp(sym, "mmap2"))
> > +		sym = "mmap_pgoff";
> > +	else if (!strcmp(sym, "statfs64_wrapper"))
> > +		sym = "statfs64";
> > +	else if (!strcmp(sym, "fstatfs64_wrapper"))
> > +		sym = "fstatfs64";
> > +	else if (!strcmp(sym, "arm_fadvise64_64"))
> > +		sym = "fadvise64_64";
> > +
> > +	return !strcmp(sym, name);
> > +}
> > +
> >  #endif /* ifndef __ASSEMBLY__ */
> >  
> >  #endif /* _ASM_ARM_FTRACE */
> > -- 
> > 2.1.4
> >   
> 

^ permalink raw reply

* [Xenomai] energy consumption of a task
From: ons jallouli @ 2016-11-14 15:40 UTC (permalink / raw)
  To: xenomai

Hello,

I need to calculate the energy consumption of a task. Any ideas how this
can be done and if there are pre-defined functions for that?

Thanks in advance,

-- 
Ons JALLOULI
Computer engineer / Ph.D Student in Computer Science
Institut d’Electronique et de Télécommunications de Rennes, Site de Nantes
Université de Nantes
Tel: +33 (0)7 50 81 33 07 <%2B33%20%280%297%2050%2091%2033%2007>

^ permalink raw reply

* Re: [qemu patch 2/2] kvmclock: reduce kvmclock difference on migration
From: Marcelo Tosatti @ 2016-11-14 15:37 UTC (permalink / raw)
  To: Juan Quintela
  Cc: kvm, qemu-devel, Dr. David Alan Gilbert, Paolo Bonzini,
	Radim Krcmar, Eduardo Habkost
In-Reply-To: <874m3af905.fsf@emacs.mitica>

On Mon, Nov 14, 2016 at 03:09:46PM +0100, Juan Quintela wrote:
> Marcelo Tosatti <mtosatti@redhat.com> wrote:
> > Check for KVM_CAP_ADJUST_CLOCK capability KVM_CLOCK_TSC_STABLE, which
> > indicates that KVM_GET_CLOCK returns a value as seen by the guest at
> > that moment.
> >
> > For new machine types, use this value rather than reading 
> > from guest memory.
> >
> > This reduces kvmclock difference on migration from 5s to 0.1s
> > (when max_downtime == 5s).
> >
> > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> Acked-by: Juan Quintela <quintela@redhat.com>
> 
> But, if you have to respin it ....
> 
> 
> > +    /* whether machine supports reliable KVM_GET_CLOCK */
> > +    bool mach_use_reliable_get_clock;
> > +
> > +    /* whether source host supported reliable KVM_GET_CLOCK */
> > +    bool src_use_reliable_get_clock;
> 
> This two names are really long, but I don't have better suggesitons :-()
> >      if (running) {
> >          struct kvm_clock_data data = {};
> > -        uint64_t time_at_migration = kvmclock_current_nsec(s);
> > +        uint64_t time_at_migration = 0;
> 
> This was not "time_at_migration", it was not already before, but just
> now it looks really weird. (as it was already faulty, this is why it is
> only a suggestion.)
> 
> >  
> > -        s->clock_valid = false;
> > +        /* local (running VM) restore */
> > +        if (s->clock_valid) {
> > +            /*
> > +             * if host does not support reliable KVM_GET_CLOCK,
> > +             * read kvmclock value from memory
> > +             */
> > +            if (!kvm_has_adjust_clock_stable()) {
> > +                time_at_migration = kvmclock_current_nsec(s);
> > +            }
> > +        /* migration/savevm/init restore */
> > +        } else {
> > +            /*
> > +             * use s->clock in case machine uses reliable
> > +             * get clock and host where vm was executing
> > +             * supported reliable get clock
> > +             */
> 
> This comment is just weird.  Simplifying
>     /* If A and B do C */
>     if (!A and || !B) {
>        then D();
>     }
> 
> Doing the opposite comment?
> 
> Migration code looks rigth.

Fixed those.

> Once said that, I continue hating clocks.

Me too, especially the biological one.


^ permalink raw reply

* Re: [qemu patch 2/2] kvmclock: reduce kvmclock difference on migration
From: Marcelo Tosatti @ 2016-11-14 15:40 UTC (permalink / raw)
  To: Paolo Bonzini
  Cc: kvm, qemu-devel, Dr. David Alan Gilbert, Juan Quintela,
	Radim Krcmar, Eduardo Habkost
In-Reply-To: <67bffd95-2e4e-7273-c154-a3fdfe622387@redhat.com>

On Mon, Nov 14, 2016 at 04:00:38PM +0100, Paolo Bonzini wrote:
> 
> 
> On 14/11/2016 15:50, Marcelo Tosatti wrote:
> > Well, i didnt want to mix the meaning of the variables:
> > 
> > +    /* whether machine supports reliable KVM_GET_CLOCK */
> > +    bool mach_use_reliable_get_clock;
> > +
> > +    /* whether source host supported reliable KVM_GET_CLOCK */
> > +    bool src_use_reliable_get_clock;
> > 
> > See the comments on top (later if you look at the variable, 
> > then have to think: well it has one name, but its disabled 
> > by that other path as well, so its more than its 
> > name,etc...).
> > 
> >> I'm thinking "mach_use_reliable_get_clock is just for migration,
> > 
> > Thats whether the machine supports it. New machines have it enabled,
> > olders don't.
> 
> Yes.
> 
> >> src_use_reliable_get_clock is the state". 
> > 
> > Thats whether the migration source supported it.
> 
> But it's not used only for migration.  It's used on every vmstate change
> (running->stop and stop->running, isn't it?  

No. Its used only if s->clock_valid == false, which means either:

migration/savevm/init.

Now for savevm there is a bug: 

> I think that, apart from
> the migration case, it's better to use s->clock if kvmclock is stable,
> even on older machine types.

Yes, its already doing that:

        /* local (running VM) restore */
        if (s->clock_valid) {
            /*
             * if host does not support reliable KVM_GET_CLOCK,
             * read kvmclock value from memory
             */
            if (!kvm_has_adjust_clock_stable()) {
                time_at_migration = kvmclock_current_nsec(s);
            }

It only uses kvmclock_current_nsec() if kvm_has_adjust_clock_stable is 
false.

> >>>>> +static bool kvmclock_src_use_reliable_get_clock(void *opaque)
> >>>>> +{
> >>>>> +    KVMClockState *s = opaque;
> >>>>> +
> >>>>> +    /*
> >>>>> +     * On machine types that support reliable KVM_GET_CLOCK,
> >>>>> +     * if host kernel does provide reliable KVM_GET_CLOCK,
> >>>>> +     * set src_use_reliable_get_clock=true so that destination
> >>>>> +     * avoids reading kvmclock from memory.
> >>>>> +     */
> >>>>> +    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable()) {
> >>>>> +        s->src_use_reliable_get_clock = true;
> >>>>> +    }
> >>>>> +
> >>>>> +    return s->src_use_reliable_get_clock;
> >>>>> +}
> >>>>
> >>>> Here you can just return s->mach_use_reliable_get_clock. 
> >>>
> >>> mach_use_reliable_get_clock can be true but host might not support it.
> >>
> >> Yes, but the "needed" function is only required to avoid breaking
> >> pc-i440fx-2.7 and earlier. 
> > 
> > "needed" is required so that the migration between:
> > 
> > SRC             DEST                BEHAVIOUR
> > ~support        supports            on migration read from guest,
> >                                     on stop/cont use
> >                                     kvm_get_clock/kvm_set_clock
> > 
> > Destination does not use KVM_GET_CLOCK value (which is
> > broken and should not be used).
> 
> If needed returns false, the destination will see
> src_use_reliable_get_clock = false anyway.

Causing it to read the clock from memory, thats what 
should happen.

> If needed returns true, the destination can still see
> src_use_reliable_get_clock = false if that's the value.

You are asking me to change from:

+static bool kvmclock_src_use_reliable_get_clock(void *opaque)
+{
+    KVMClockState *s = opaque;
+
+    /*
+     * On machine types that support reliable KVM_GET_CLOCK,
+     * if host kernel does provide reliable KVM_GET_CLOCK,
+     * set src_use_reliable_get_clock=true so that destination
+     * avoids reading kvmclock from memory.
+     */
+    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable()) {
+        s->src_use_reliable_get_clock = true;
+    }
+
+    return s->src_use_reliable_get_clock;
+}

to

static bool kvmclock_src_use_reliable_get_clock(void *opaque)
{
    KVMClockState *s = opaque;

    /*
     * On machine types that support reliable KVM_GET_CLOCK,
     * if host kernel does provide reliable KVM_GET_CLOCK,
     * set src_use_reliable_get_clock=true so that destination
     * avoids reading kvmclock from memory.
     */
    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable())
    {
        s->src_use_reliable_get_clock = true;
    }

    return s->mach_use_reliable_get_clock;
}


Ah, OK, done.


> needed	src_use_reliable_get_clock	effect
> false	false				use kvmclock_current_nsec
> false	true				use kvmclock_current_nsec
> true	false				use kvmclock_current_nsec
> true	true				use s->clock
> 
> 
> So the idea is:
> 
> - set s->clock and s->reliable_get_clock on every KVM_GET_CLOCK

Already do that (apart from s->clock_valid which is necessary).

> - on migration source, use subsections and
> s->mach_use_reliable_get_clock to avoid breaking migration on pre-2.8
> machine types

Migration is already broken when you use different machine types.

So s->src_use_reliable_get_clock is only used to indicate 
to the destination that: "you can use KVM_GET_CLOCK value, 
its safe".

> - on migration destination, use .pre_load so that s->reliable_get_clock
> is initialized to false on older machine types

Thats what mach_use_reliable_get_clock does already:

static Property kvmclock_properties[] = {
    DEFINE_PROP_BOOL("mach_use_reliable_get_clock", KVMClockState,
                      mach_use_reliable_get_clock, true),
    DEFINE_PROP_END_OF_LIST(),
};

+        .driver   = "kvmclock",\
+        .property = "mach_use_reliable_get_clock",\
+        .value    = "off",\
+    },\
+    {\

> 
> >> If you return true here, you can still
> >> migrate a "false" value for src_use_reliable_get_clock.
> > 
> > But the source only uses a reliable KVM_GET_CLOCK if 
> > both conditions are true.
> > 
> > And the subsection is only needed if the source
> > uses a reliable KVM_GET_CLOCK.
> 
> Yes, but the point of the subsection is just to avoid breaking migration
> format.

Its a new creative use of the subsection. 

> >> It is the same as "is using masterclock", which is actually a stricter
> >> condition than the KVM_CHECK_EXTENSION return value.  The right check to
> >> use is whether masterclock is in use, 
> > 
> > Actually its "has a reliable KVM_GET_CLOCK" (which returns 
> > get_kernel_clock() + (rdtsc() - tsc_timestamp), 
> > 
> > "broken KVM_GET_CLOCK" =  get_kernel_clock()
> 
> Yes.  And these end up being the same.

No. You can have masterclock enabled, KVM_TSC_STABLE set in pvclock
flags, and unreliable KVM_GET_CLOCK (without your patch to
KVM_GET_CLOCK).


Paolo not sure if there is anything further you want me to 
change at this point ? 


Index: qemu-mig-advance-clock/hw/i386/kvm/clock.c
===================================================================
--- qemu-mig-advance-clock.orig/hw/i386/kvm/clock.c	2016-11-14 10:40:39.748116312 -0200
+++ qemu-mig-advance-clock/hw/i386/kvm/clock.c	2016-11-14 13:38:29.299955042 -0200
@@ -36,6 +36,12 @@
 
     uint64_t clock;
     bool clock_valid;
+
+    /* whether machine supports reliable KVM_GET_CLOCK */
+    bool mach_use_reliable_get_clock;
+
+    /* whether source host supported reliable KVM_GET_CLOCK */
+    bool src_use_reliable_get_clock;
 } KVMClockState;
 
 struct pvclock_vcpu_time_info {
@@ -81,6 +87,19 @@
     return nsec + time.system_time;
 }
 
+static uint64_t kvm_get_clock(void)
+{
+    struct kvm_clock_data data;
+    int ret;
+
+    ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
+    if (ret < 0) {
+        fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
+                abort();
+    }
+    return data.clock;
+}
+
 static void kvmclock_vm_state_change(void *opaque, int running,
                                      RunState state)
 {
@@ -91,15 +110,37 @@
 
     if (running) {
         struct kvm_clock_data data = {};
-        uint64_t time_at_migration = kvmclock_current_nsec(s);
+        uint64_t pvclock_via_mem = 0;
 
-        s->clock_valid = false;
+        /* local (running VM) restore */
+        if (s->clock_valid) {
+            /*
+             * if host does not support reliable KVM_GET_CLOCK,
+             * read kvmclock value from memory
+             */
+            if (!kvm_has_adjust_clock_stable()) {
+                pvclock_via_mem = kvmclock_current_nsec(s);
+            }
+        /* migration/savevm/init restore */
+        } else {
+            /*
+             * use s->clock in case machine uses reliable
+             * get clock and source host supported
+             * reliable get clock
+             */
+            if (!(s->mach_use_reliable_get_clock &&
+                  s->src_use_reliable_get_clock)) {
+                pvclock_via_mem = kvmclock_current_nsec(s);
+            }
+        }
 
-        /* We can't rely on the migrated clock value, just discard it */
-        if (time_at_migration) {
-            s->clock = time_at_migration;
+        /* We can't rely on the saved clock value, just discard it */
+        if (pvclock_via_mem) {
+            s->clock = pvclock_via_mem;
         }
 
+        s->clock_valid = false;
+
         data.clock = s->clock;
         ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
         if (ret < 0) {
@@ -120,8 +161,6 @@
             }
         }
     } else {
-        struct kvm_clock_data data;
-        int ret;
 
         if (s->clock_valid) {
             return;
@@ -129,13 +168,7 @@
 
         kvm_synchronize_all_tsc();
 
-        ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
-        if (ret < 0) {
-            fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
-            abort();
-        }
-        s->clock = data.clock;
-
+        s->clock = kvm_get_clock();
         /*
          * If the VM is stopped, declare the clock state valid to
          * avoid re-reading it on next vmsave (which would return
@@ -152,22 +185,69 @@
     qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
 }
 
+static bool kvmclock_src_use_reliable_get_clock(void *opaque)
+{
+    KVMClockState *s = opaque;
+
+    /*
+     * On machine types that support reliable KVM_GET_CLOCK,
+     * if host kernel does provide reliable KVM_GET_CLOCK,
+     * set src_use_reliable_get_clock=true so that destination
+     * avoids reading kvmclock from memory.
+     */
+    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable()) {
+        s->src_use_reliable_get_clock = true;
+    }
+
+    return s->mach_use_reliable_get_clock;
+}
+
+static const VMStateDescription kvmclock_reliable_get_clock = {
+    .name = "kvmclock/src_use_reliable_get_clock",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = kvmclock_src_use_reliable_get_clock,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(src_use_reliable_get_clock, KVMClockState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void kvmclock_pre_save(void *opaque)
+{
+    KVMClockState *s = opaque;
+
+    s->clock = kvm_get_clock();
+}
+
 static const VMStateDescription kvmclock_vmsd = {
     .name = "kvmclock",
     .version_id = 1,
     .minimum_version_id = 1,
+    .pre_save = kvmclock_pre_save,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(clock, KVMClockState),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription * []) {
+        &kvmclock_reliable_get_clock,
+        NULL
     }
 };
 
+static Property kvmclock_properties[] = {
+    DEFINE_PROP_BOOL("mach_use_reliable_get_clock", KVMClockState,
+                      mach_use_reliable_get_clock, true),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void kvmclock_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = kvmclock_realize;
     dc->vmsd = &kvmclock_vmsd;
+    dc->props = kvmclock_properties;
 }
 
 static const TypeInfo kvmclock_info = {
Index: qemu-mig-advance-clock/include/hw/i386/pc.h
===================================================================
--- qemu-mig-advance-clock.orig/include/hw/i386/pc.h	2016-11-14 10:40:39.748116312 -0200
+++ qemu-mig-advance-clock/include/hw/i386/pc.h	2016-11-14 10:40:48.059128649 -0200
@@ -370,6 +370,11 @@
 #define PC_COMPAT_2_7 \
     HW_COMPAT_2_7 \
     {\
+        .driver   = "kvmclock",\
+        .property = "mach_use_reliable_get_clock",\
+        .value    = "off",\
+    },\
+    {\
         .driver   = TYPE_X86_CPU,\
         .property = "l3-cache",\
         .value    = "off",\
Index: qemu-mig-advance-clock/target-i386/kvm.c
===================================================================
--- qemu-mig-advance-clock.orig/target-i386/kvm.c	2016-11-14 10:40:39.750116314 -0200
+++ qemu-mig-advance-clock/target-i386/kvm.c	2016-11-14 10:40:48.061128652 -0200
@@ -117,6 +117,13 @@
     return kvm_check_extension(kvm_state, KVM_CAP_X86_SMM);
 }
 
+bool kvm_has_adjust_clock_stable(void)
+{
+    int ret = kvm_check_extension(kvm_state, KVM_CAP_ADJUST_CLOCK);
+
+    return (ret == KVM_CLOCK_TSC_STABLE);
+}
+
 bool kvm_allows_irq0_override(void)
 {
     return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing();
Index: qemu-mig-advance-clock/target-i386/kvm_i386.h
===================================================================
--- qemu-mig-advance-clock.orig/target-i386/kvm_i386.h	2016-11-14 10:40:39.751116316 -0200
+++ qemu-mig-advance-clock/target-i386/kvm_i386.h	2016-11-14 10:40:48.061128652 -0200
@@ -17,6 +17,7 @@
 
 bool kvm_allows_irq0_override(void);
 bool kvm_has_smm(void);
+bool kvm_has_adjust_clock_stable(void);
 void kvm_synchronize_all_tsc(void);
 void kvm_arch_reset_vcpu(X86CPU *cs);
 void kvm_arch_do_init_vcpu(X86CPU *cs);

^ permalink raw reply

* Re: [Qemu-devel] [PATCH for-2.8 0/2] pc: remove redundant fw_cfg file "etc/boot-cpus"
From: Stefan Hajnoczi @ 2016-11-14 15:40 UTC (permalink / raw)
  To: Igor Mammedov
  Cc: qemu-devel, Eduardo Habkost, mst, Kevin O'Connor,
	Gerd Hoffmann, Laszlo Ersek
In-Reply-To: <1478877672-73759-1-git-send-email-imammedo@redhat.com>

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On Fri, Nov 11, 2016 at 04:21:10PM +0100, Igor Mammedov wrote:
> 
> Commit 080ac219cc7d9c55adf925c3545b7450055ad625
>    pc: Add 'etc/boot-cpus' fw_cfg file for machine with more than 255 CPUs
> 
> added "etc/boot-cpus" fw_cfg file durung 2.8 merge window, however
> QEMU alredy had similar legacy FW_CFG_NB_CPUS fw_cfg entry that
> should do practically the same. Considering FW_CFG_NB_CPUS's been
> around for a long time and is used by external projects (firmwares)
> we can't replace it with 'etc/boot-cpus' fw_cfg file.
> 
> Drop redundant 'etc/boot-cpus' fw_cfg file  and reuse FW_CFG_NB_CPUS
> instead.
> 
> So here goes QEMU part of fixup
> 
> CC: Eduardo Habkost <ehabkost@redhat.com>
> CC: mst@redhat.com
> CC: Stefan Hajnoczi <stefanha@gmail.com>
> CC: "Kevin O'Connor" <kevin@koconnor.net>
> CC: Gerd Hoffmann <kraxel@redhat.com>
> CC: Laszlo Ersek <lersek@redhat.com>
> 
> Igor Mammedov (2):
>   fw_cfg: move FW_CFG_NB_CPUS out of fw_cfg_init1()
>   pc: drop "etc/boot-cpus" fw_cfg file and use FW_CFG_NB_CPUS instead
> 
>  include/hw/i386/pc.h  |  4 ++--
>  hw/arm/virt.c         |  4 +++-
>  hw/i386/pc.c          | 20 ++++++++------------
>  hw/nvram/fw_cfg.c     |  1 -
>  hw/ppc/mac_newworld.c |  1 +
>  hw/ppc/mac_oldworld.c |  1 +
>  hw/sparc/sun4m.c      |  1 +
>  hw/sparc64/sun4u.c    |  1 +
>  8 files changed, 17 insertions(+), 16 deletions(-)

Thanks, this should go through Eduardo's tree.

Stefan

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^ permalink raw reply

* Re: [Qemu-devel] [qemu patch 2/2] kvmclock: reduce kvmclock difference on migration
From: Marcelo Tosatti @ 2016-11-14 15:37 UTC (permalink / raw)
  To: Juan Quintela
  Cc: kvm, qemu-devel, Dr. David Alan Gilbert, Paolo Bonzini,
	Radim Krcmar, Eduardo Habkost
In-Reply-To: <874m3af905.fsf@emacs.mitica>

On Mon, Nov 14, 2016 at 03:09:46PM +0100, Juan Quintela wrote:
> Marcelo Tosatti <mtosatti@redhat.com> wrote:
> > Check for KVM_CAP_ADJUST_CLOCK capability KVM_CLOCK_TSC_STABLE, which
> > indicates that KVM_GET_CLOCK returns a value as seen by the guest at
> > that moment.
> >
> > For new machine types, use this value rather than reading 
> > from guest memory.
> >
> > This reduces kvmclock difference on migration from 5s to 0.1s
> > (when max_downtime == 5s).
> >
> > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> Acked-by: Juan Quintela <quintela@redhat.com>
> 
> But, if you have to respin it ....
> 
> 
> > +    /* whether machine supports reliable KVM_GET_CLOCK */
> > +    bool mach_use_reliable_get_clock;
> > +
> > +    /* whether source host supported reliable KVM_GET_CLOCK */
> > +    bool src_use_reliable_get_clock;
> 
> This two names are really long, but I don't have better suggesitons :-()
> >      if (running) {
> >          struct kvm_clock_data data = {};
> > -        uint64_t time_at_migration = kvmclock_current_nsec(s);
> > +        uint64_t time_at_migration = 0;
> 
> This was not "time_at_migration", it was not already before, but just
> now it looks really weird. (as it was already faulty, this is why it is
> only a suggestion.)
> 
> >  
> > -        s->clock_valid = false;
> > +        /* local (running VM) restore */
> > +        if (s->clock_valid) {
> > +            /*
> > +             * if host does not support reliable KVM_GET_CLOCK,
> > +             * read kvmclock value from memory
> > +             */
> > +            if (!kvm_has_adjust_clock_stable()) {
> > +                time_at_migration = kvmclock_current_nsec(s);
> > +            }
> > +        /* migration/savevm/init restore */
> > +        } else {
> > +            /*
> > +             * use s->clock in case machine uses reliable
> > +             * get clock and host where vm was executing
> > +             * supported reliable get clock
> > +             */
> 
> This comment is just weird.  Simplifying
>     /* If A and B do C */
>     if (!A and || !B) {
>        then D();
>     }
> 
> Doing the opposite comment?
> 
> Migration code looks rigth.

Fixed those.

> Once said that, I continue hating clocks.

Me too, especially the biological one.

^ permalink raw reply

* Re: [Qemu-devel] [qemu patch 2/2] kvmclock: reduce kvmclock difference on migration
From: Marcelo Tosatti @ 2016-11-14 15:40 UTC (permalink / raw)
  To: Paolo Bonzini
  Cc: kvm, qemu-devel, Dr. David Alan Gilbert, Juan Quintela,
	Radim Krcmar, Eduardo Habkost
In-Reply-To: <67bffd95-2e4e-7273-c154-a3fdfe622387@redhat.com>

On Mon, Nov 14, 2016 at 04:00:38PM +0100, Paolo Bonzini wrote:
> 
> 
> On 14/11/2016 15:50, Marcelo Tosatti wrote:
> > Well, i didnt want to mix the meaning of the variables:
> > 
> > +    /* whether machine supports reliable KVM_GET_CLOCK */
> > +    bool mach_use_reliable_get_clock;
> > +
> > +    /* whether source host supported reliable KVM_GET_CLOCK */
> > +    bool src_use_reliable_get_clock;
> > 
> > See the comments on top (later if you look at the variable, 
> > then have to think: well it has one name, but its disabled 
> > by that other path as well, so its more than its 
> > name,etc...).
> > 
> >> I'm thinking "mach_use_reliable_get_clock is just for migration,
> > 
> > Thats whether the machine supports it. New machines have it enabled,
> > olders don't.
> 
> Yes.
> 
> >> src_use_reliable_get_clock is the state". 
> > 
> > Thats whether the migration source supported it.
> 
> But it's not used only for migration.  It's used on every vmstate change
> (running->stop and stop->running, isn't it?  

No. Its used only if s->clock_valid == false, which means either:

migration/savevm/init.

Now for savevm there is a bug: 

> I think that, apart from
> the migration case, it's better to use s->clock if kvmclock is stable,
> even on older machine types.

Yes, its already doing that:

        /* local (running VM) restore */
        if (s->clock_valid) {
            /*
             * if host does not support reliable KVM_GET_CLOCK,
             * read kvmclock value from memory
             */
            if (!kvm_has_adjust_clock_stable()) {
                time_at_migration = kvmclock_current_nsec(s);
            }

It only uses kvmclock_current_nsec() if kvm_has_adjust_clock_stable is 
false.

> >>>>> +static bool kvmclock_src_use_reliable_get_clock(void *opaque)
> >>>>> +{
> >>>>> +    KVMClockState *s = opaque;
> >>>>> +
> >>>>> +    /*
> >>>>> +     * On machine types that support reliable KVM_GET_CLOCK,
> >>>>> +     * if host kernel does provide reliable KVM_GET_CLOCK,
> >>>>> +     * set src_use_reliable_get_clock=true so that destination
> >>>>> +     * avoids reading kvmclock from memory.
> >>>>> +     */
> >>>>> +    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable()) {
> >>>>> +        s->src_use_reliable_get_clock = true;
> >>>>> +    }
> >>>>> +
> >>>>> +    return s->src_use_reliable_get_clock;
> >>>>> +}
> >>>>
> >>>> Here you can just return s->mach_use_reliable_get_clock. 
> >>>
> >>> mach_use_reliable_get_clock can be true but host might not support it.
> >>
> >> Yes, but the "needed" function is only required to avoid breaking
> >> pc-i440fx-2.7 and earlier. 
> > 
> > "needed" is required so that the migration between:
> > 
> > SRC             DEST                BEHAVIOUR
> > ~support        supports            on migration read from guest,
> >                                     on stop/cont use
> >                                     kvm_get_clock/kvm_set_clock
> > 
> > Destination does not use KVM_GET_CLOCK value (which is
> > broken and should not be used).
> 
> If needed returns false, the destination will see
> src_use_reliable_get_clock = false anyway.

Causing it to read the clock from memory, thats what 
should happen.

> If needed returns true, the destination can still see
> src_use_reliable_get_clock = false if that's the value.

You are asking me to change from:

+static bool kvmclock_src_use_reliable_get_clock(void *opaque)
+{
+    KVMClockState *s = opaque;
+
+    /*
+     * On machine types that support reliable KVM_GET_CLOCK,
+     * if host kernel does provide reliable KVM_GET_CLOCK,
+     * set src_use_reliable_get_clock=true so that destination
+     * avoids reading kvmclock from memory.
+     */
+    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable()) {
+        s->src_use_reliable_get_clock = true;
+    }
+
+    return s->src_use_reliable_get_clock;
+}

to

static bool kvmclock_src_use_reliable_get_clock(void *opaque)
{
    KVMClockState *s = opaque;

    /*
     * On machine types that support reliable KVM_GET_CLOCK,
     * if host kernel does provide reliable KVM_GET_CLOCK,
     * set src_use_reliable_get_clock=true so that destination
     * avoids reading kvmclock from memory.
     */
    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable())
    {
        s->src_use_reliable_get_clock = true;
    }

    return s->mach_use_reliable_get_clock;
}


Ah, OK, done.


> needed	src_use_reliable_get_clock	effect
> false	false				use kvmclock_current_nsec
> false	true				use kvmclock_current_nsec
> true	false				use kvmclock_current_nsec
> true	true				use s->clock
> 
> 
> So the idea is:
> 
> - set s->clock and s->reliable_get_clock on every KVM_GET_CLOCK

Already do that (apart from s->clock_valid which is necessary).

> - on migration source, use subsections and
> s->mach_use_reliable_get_clock to avoid breaking migration on pre-2.8
> machine types

Migration is already broken when you use different machine types.

So s->src_use_reliable_get_clock is only used to indicate 
to the destination that: "you can use KVM_GET_CLOCK value, 
its safe".

> - on migration destination, use .pre_load so that s->reliable_get_clock
> is initialized to false on older machine types

Thats what mach_use_reliable_get_clock does already:

static Property kvmclock_properties[] = {
    DEFINE_PROP_BOOL("mach_use_reliable_get_clock", KVMClockState,
                      mach_use_reliable_get_clock, true),
    DEFINE_PROP_END_OF_LIST(),
};

+        .driver   = "kvmclock",\
+        .property = "mach_use_reliable_get_clock",\
+        .value    = "off",\
+    },\
+    {\

> 
> >> If you return true here, you can still
> >> migrate a "false" value for src_use_reliable_get_clock.
> > 
> > But the source only uses a reliable KVM_GET_CLOCK if 
> > both conditions are true.
> > 
> > And the subsection is only needed if the source
> > uses a reliable KVM_GET_CLOCK.
> 
> Yes, but the point of the subsection is just to avoid breaking migration
> format.

Its a new creative use of the subsection. 

> >> It is the same as "is using masterclock", which is actually a stricter
> >> condition than the KVM_CHECK_EXTENSION return value.  The right check to
> >> use is whether masterclock is in use, 
> > 
> > Actually its "has a reliable KVM_GET_CLOCK" (which returns 
> > get_kernel_clock() + (rdtsc() - tsc_timestamp), 
> > 
> > "broken KVM_GET_CLOCK" =  get_kernel_clock()
> 
> Yes.  And these end up being the same.

No. You can have masterclock enabled, KVM_TSC_STABLE set in pvclock
flags, and unreliable KVM_GET_CLOCK (without your patch to
KVM_GET_CLOCK).


Paolo not sure if there is anything further you want me to 
change at this point ? 


Index: qemu-mig-advance-clock/hw/i386/kvm/clock.c
===================================================================
--- qemu-mig-advance-clock.orig/hw/i386/kvm/clock.c	2016-11-14 10:40:39.748116312 -0200
+++ qemu-mig-advance-clock/hw/i386/kvm/clock.c	2016-11-14 13:38:29.299955042 -0200
@@ -36,6 +36,12 @@
 
     uint64_t clock;
     bool clock_valid;
+
+    /* whether machine supports reliable KVM_GET_CLOCK */
+    bool mach_use_reliable_get_clock;
+
+    /* whether source host supported reliable KVM_GET_CLOCK */
+    bool src_use_reliable_get_clock;
 } KVMClockState;
 
 struct pvclock_vcpu_time_info {
@@ -81,6 +87,19 @@
     return nsec + time.system_time;
 }
 
+static uint64_t kvm_get_clock(void)
+{
+    struct kvm_clock_data data;
+    int ret;
+
+    ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
+    if (ret < 0) {
+        fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
+                abort();
+    }
+    return data.clock;
+}
+
 static void kvmclock_vm_state_change(void *opaque, int running,
                                      RunState state)
 {
@@ -91,15 +110,37 @@
 
     if (running) {
         struct kvm_clock_data data = {};
-        uint64_t time_at_migration = kvmclock_current_nsec(s);
+        uint64_t pvclock_via_mem = 0;
 
-        s->clock_valid = false;
+        /* local (running VM) restore */
+        if (s->clock_valid) {
+            /*
+             * if host does not support reliable KVM_GET_CLOCK,
+             * read kvmclock value from memory
+             */
+            if (!kvm_has_adjust_clock_stable()) {
+                pvclock_via_mem = kvmclock_current_nsec(s);
+            }
+        /* migration/savevm/init restore */
+        } else {
+            /*
+             * use s->clock in case machine uses reliable
+             * get clock and source host supported
+             * reliable get clock
+             */
+            if (!(s->mach_use_reliable_get_clock &&
+                  s->src_use_reliable_get_clock)) {
+                pvclock_via_mem = kvmclock_current_nsec(s);
+            }
+        }
 
-        /* We can't rely on the migrated clock value, just discard it */
-        if (time_at_migration) {
-            s->clock = time_at_migration;
+        /* We can't rely on the saved clock value, just discard it */
+        if (pvclock_via_mem) {
+            s->clock = pvclock_via_mem;
         }
 
+        s->clock_valid = false;
+
         data.clock = s->clock;
         ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
         if (ret < 0) {
@@ -120,8 +161,6 @@
             }
         }
     } else {
-        struct kvm_clock_data data;
-        int ret;
 
         if (s->clock_valid) {
             return;
@@ -129,13 +168,7 @@
 
         kvm_synchronize_all_tsc();
 
-        ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
-        if (ret < 0) {
-            fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
-            abort();
-        }
-        s->clock = data.clock;
-
+        s->clock = kvm_get_clock();
         /*
          * If the VM is stopped, declare the clock state valid to
          * avoid re-reading it on next vmsave (which would return
@@ -152,22 +185,69 @@
     qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
 }
 
+static bool kvmclock_src_use_reliable_get_clock(void *opaque)
+{
+    KVMClockState *s = opaque;
+
+    /*
+     * On machine types that support reliable KVM_GET_CLOCK,
+     * if host kernel does provide reliable KVM_GET_CLOCK,
+     * set src_use_reliable_get_clock=true so that destination
+     * avoids reading kvmclock from memory.
+     */
+    if (s->mach_use_reliable_get_clock && kvm_has_adjust_clock_stable()) {
+        s->src_use_reliable_get_clock = true;
+    }
+
+    return s->mach_use_reliable_get_clock;
+}
+
+static const VMStateDescription kvmclock_reliable_get_clock = {
+    .name = "kvmclock/src_use_reliable_get_clock",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = kvmclock_src_use_reliable_get_clock,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(src_use_reliable_get_clock, KVMClockState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void kvmclock_pre_save(void *opaque)
+{
+    KVMClockState *s = opaque;
+
+    s->clock = kvm_get_clock();
+}
+
 static const VMStateDescription kvmclock_vmsd = {
     .name = "kvmclock",
     .version_id = 1,
     .minimum_version_id = 1,
+    .pre_save = kvmclock_pre_save,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(clock, KVMClockState),
         VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription * []) {
+        &kvmclock_reliable_get_clock,
+        NULL
     }
 };
 
+static Property kvmclock_properties[] = {
+    DEFINE_PROP_BOOL("mach_use_reliable_get_clock", KVMClockState,
+                      mach_use_reliable_get_clock, true),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void kvmclock_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = kvmclock_realize;
     dc->vmsd = &kvmclock_vmsd;
+    dc->props = kvmclock_properties;
 }
 
 static const TypeInfo kvmclock_info = {
Index: qemu-mig-advance-clock/include/hw/i386/pc.h
===================================================================
--- qemu-mig-advance-clock.orig/include/hw/i386/pc.h	2016-11-14 10:40:39.748116312 -0200
+++ qemu-mig-advance-clock/include/hw/i386/pc.h	2016-11-14 10:40:48.059128649 -0200
@@ -370,6 +370,11 @@
 #define PC_COMPAT_2_7 \
     HW_COMPAT_2_7 \
     {\
+        .driver   = "kvmclock",\
+        .property = "mach_use_reliable_get_clock",\
+        .value    = "off",\
+    },\
+    {\
         .driver   = TYPE_X86_CPU,\
         .property = "l3-cache",\
         .value    = "off",\
Index: qemu-mig-advance-clock/target-i386/kvm.c
===================================================================
--- qemu-mig-advance-clock.orig/target-i386/kvm.c	2016-11-14 10:40:39.750116314 -0200
+++ qemu-mig-advance-clock/target-i386/kvm.c	2016-11-14 10:40:48.061128652 -0200
@@ -117,6 +117,13 @@
     return kvm_check_extension(kvm_state, KVM_CAP_X86_SMM);
 }
 
+bool kvm_has_adjust_clock_stable(void)
+{
+    int ret = kvm_check_extension(kvm_state, KVM_CAP_ADJUST_CLOCK);
+
+    return (ret == KVM_CLOCK_TSC_STABLE);
+}
+
 bool kvm_allows_irq0_override(void)
 {
     return !kvm_irqchip_in_kernel() || kvm_has_gsi_routing();
Index: qemu-mig-advance-clock/target-i386/kvm_i386.h
===================================================================
--- qemu-mig-advance-clock.orig/target-i386/kvm_i386.h	2016-11-14 10:40:39.751116316 -0200
+++ qemu-mig-advance-clock/target-i386/kvm_i386.h	2016-11-14 10:40:48.061128652 -0200
@@ -17,6 +17,7 @@
 
 bool kvm_allows_irq0_override(void);
 bool kvm_has_smm(void);
+bool kvm_has_adjust_clock_stable(void);
 void kvm_synchronize_all_tsc(void);
 void kvm_arch_reset_vcpu(X86CPU *cs);
 void kvm_arch_do_init_vcpu(X86CPU *cs);

^ permalink raw reply

* [PATCH v12 00/22] Add Mediated device support
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede

This series adds Mediated device support to Linux host kernel. Purpose
of this series is to provide a common interface for mediated device
management that can be used by different devices. This series introduces
Mdev core module that creates and manages mediated devices, VFIO based
driver for mediated devices that are created by mdev core module and
update VFIO type1 IOMMU module to support pinning & unpinning for mediated
devices.

What changed v11-> v12?
vfio_iommu_type1:
- Pinned pages are tracked in vfio_dma structure for that range, dma->iova
  to dma->iova + dma->size.
- Key for pfn_list rb-tree is iova, instead of pfn.
- Removing address space structure. vfio_dma keeps task structure, which
  is used to get mm structure (using get_task_mm(task) and mmput(mm)) for
  pin/unpin and page accounting.
- vfio_unpin_pages() has array of user_pfns as input argument, instead of
  array of pfns.
- On vfio_pin_pages(), pinning happens once. On later call to
  vfio_pin_pages() with same user_pfn, if iova is found in pfn_list, only
  ref_count is incremented.
- In vfio_unpin_pages(), ref_count is decremented and page is unpinned
  when ref_count is 0.
- For vfio_pin_pages() and vfio_unpin_pages() input array, number of
  elements in array should be less that PAGE_SIZE. If vendor driver wants
  to use for more pages, array should  be split it in chunks of PAGE_SIZE.
- Updating page accounting logic with above changes.

Tested by assigning below combinations of devices to a single VM:
- GPU pass through only
- vGPU device only
- One GPU pass through and one vGPU device
- Linux VM hot plug and unplug vGPU device while GPU pass through device
  exist
- Linux VM hot plug and unplug GPU pass through device while vGPU device
  exist

Tested with Linux 4.9-rc5

Kirti Wankhede (22):
  vfio: Mediated device Core driver
  vfio: VFIO based driver for Mediated devices
  vfio: Rearrange functions to get vfio_group from dev
  vfio: Common function to increment container_users
  vfio iommu: Added pin and unpin callback functions to
    vfio_iommu_driver_ops
  vfio iommu type1: Update arguments of vfio_lock_acct
  vfio iommu type1: Update argument of vaddr_get_pfn()
  vfio iommu type1: Add find_iommu_group() function
  vfio iommu type1: Add task structure to vfio_dma
  vfio iommu type1: Add support for mediated devices
  vfio iommu: Add blocking notifier to notify DMA_UNMAP
  vfio: Add notifier callback to parent's ops structure of mdev
  vfio: Introduce common function to add capabilities
  vfio_pci: Update vfio_pci to use vfio_info_add_capability()
  vfio: Introduce vfio_set_irqs_validate_and_prepare()
  vfio_pci: Updated to use vfio_set_irqs_validate_and_prepare()
  vfio_platform: Updated to use vfio_set_irqs_validate_and_prepare()
  vfio: Define device_api strings
  docs: Add Documentation for Mediated devices
  docs: Sysfs ABI for mediated device framework
  docs: Sample driver to demonstrate how to use Mediated device
    framework.
  MAINTAINERS: Add entry VFIO based Mediated device drivers

 Documentation/ABI/testing/sysfs-bus-vfio-mdev |  111 ++
 Documentation/vfio-mediated-device.txt        |  399 +++++++
 MAINTAINERS                                   |    9 +
 drivers/vfio/Kconfig                          |    1 +
 drivers/vfio/Makefile                         |    1 +
 drivers/vfio/mdev/Kconfig                     |   17 +
 drivers/vfio/mdev/Makefile                    |    5 +
 drivers/vfio/mdev/mdev_core.c                 |  388 +++++++
 drivers/vfio/mdev/mdev_driver.c               |  120 ++
 drivers/vfio/mdev/mdev_private.h              |   41 +
 drivers/vfio/mdev/mdev_sysfs.c                |  286 +++++
 drivers/vfio/mdev/vfio_mdev.c                 |  167 +++
 drivers/vfio/pci/vfio_pci.c                   |   83 +-
 drivers/vfio/platform/vfio_platform_common.c  |   31 +-
 drivers/vfio/vfio.c                           |  341 +++++-
 drivers/vfio/vfio_iommu_type1.c               |  831 +++++++++++---
 include/linux/mdev.h                          |  177 +++
 include/linux/vfio.h                          |   30 +-
 include/uapi/linux/vfio.h                     |   10 +
 samples/vfio-mdev/Makefile                    |   13 +
 samples/vfio-mdev/mtty.c                      | 1503 +++++++++++++++++++++++++
 21 files changed, 4328 insertions(+), 236 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-vfio-mdev
 create mode 100644 Documentation/vfio-mediated-device.txt
 create mode 100644 drivers/vfio/mdev/Kconfig
 create mode 100644 drivers/vfio/mdev/Makefile
 create mode 100644 drivers/vfio/mdev/mdev_core.c
 create mode 100644 drivers/vfio/mdev/mdev_driver.c
 create mode 100644 drivers/vfio/mdev/mdev_private.h
 create mode 100644 drivers/vfio/mdev/mdev_sysfs.c
 create mode 100644 drivers/vfio/mdev/vfio_mdev.c
 create mode 100644 include/linux/mdev.h
 create mode 100644 samples/vfio-mdev/Makefile
 create mode 100644 samples/vfio-mdev/mtty.c

-- 
2.7.0


^ permalink raw reply

* [Qemu-devel] [PATCH v12 00/22] Add Mediated device support
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede

This series adds Mediated device support to Linux host kernel. Purpose
of this series is to provide a common interface for mediated device
management that can be used by different devices. This series introduces
Mdev core module that creates and manages mediated devices, VFIO based
driver for mediated devices that are created by mdev core module and
update VFIO type1 IOMMU module to support pinning & unpinning for mediated
devices.

What changed v11-> v12?
vfio_iommu_type1:
- Pinned pages are tracked in vfio_dma structure for that range, dma->iova
  to dma->iova + dma->size.
- Key for pfn_list rb-tree is iova, instead of pfn.
- Removing address space structure. vfio_dma keeps task structure, which
  is used to get mm structure (using get_task_mm(task) and mmput(mm)) for
  pin/unpin and page accounting.
- vfio_unpin_pages() has array of user_pfns as input argument, instead of
  array of pfns.
- On vfio_pin_pages(), pinning happens once. On later call to
  vfio_pin_pages() with same user_pfn, if iova is found in pfn_list, only
  ref_count is incremented.
- In vfio_unpin_pages(), ref_count is decremented and page is unpinned
  when ref_count is 0.
- For vfio_pin_pages() and vfio_unpin_pages() input array, number of
  elements in array should be less that PAGE_SIZE. If vendor driver wants
  to use for more pages, array should  be split it in chunks of PAGE_SIZE.
- Updating page accounting logic with above changes.

Tested by assigning below combinations of devices to a single VM:
- GPU pass through only
- vGPU device only
- One GPU pass through and one vGPU device
- Linux VM hot plug and unplug vGPU device while GPU pass through device
  exist
- Linux VM hot plug and unplug GPU pass through device while vGPU device
  exist

Tested with Linux 4.9-rc5

Kirti Wankhede (22):
  vfio: Mediated device Core driver
  vfio: VFIO based driver for Mediated devices
  vfio: Rearrange functions to get vfio_group from dev
  vfio: Common function to increment container_users
  vfio iommu: Added pin and unpin callback functions to
    vfio_iommu_driver_ops
  vfio iommu type1: Update arguments of vfio_lock_acct
  vfio iommu type1: Update argument of vaddr_get_pfn()
  vfio iommu type1: Add find_iommu_group() function
  vfio iommu type1: Add task structure to vfio_dma
  vfio iommu type1: Add support for mediated devices
  vfio iommu: Add blocking notifier to notify DMA_UNMAP
  vfio: Add notifier callback to parent's ops structure of mdev
  vfio: Introduce common function to add capabilities
  vfio_pci: Update vfio_pci to use vfio_info_add_capability()
  vfio: Introduce vfio_set_irqs_validate_and_prepare()
  vfio_pci: Updated to use vfio_set_irqs_validate_and_prepare()
  vfio_platform: Updated to use vfio_set_irqs_validate_and_prepare()
  vfio: Define device_api strings
  docs: Add Documentation for Mediated devices
  docs: Sysfs ABI for mediated device framework
  docs: Sample driver to demonstrate how to use Mediated device
    framework.
  MAINTAINERS: Add entry VFIO based Mediated device drivers

 Documentation/ABI/testing/sysfs-bus-vfio-mdev |  111 ++
 Documentation/vfio-mediated-device.txt        |  399 +++++++
 MAINTAINERS                                   |    9 +
 drivers/vfio/Kconfig                          |    1 +
 drivers/vfio/Makefile                         |    1 +
 drivers/vfio/mdev/Kconfig                     |   17 +
 drivers/vfio/mdev/Makefile                    |    5 +
 drivers/vfio/mdev/mdev_core.c                 |  388 +++++++
 drivers/vfio/mdev/mdev_driver.c               |  120 ++
 drivers/vfio/mdev/mdev_private.h              |   41 +
 drivers/vfio/mdev/mdev_sysfs.c                |  286 +++++
 drivers/vfio/mdev/vfio_mdev.c                 |  167 +++
 drivers/vfio/pci/vfio_pci.c                   |   83 +-
 drivers/vfio/platform/vfio_platform_common.c  |   31 +-
 drivers/vfio/vfio.c                           |  341 +++++-
 drivers/vfio/vfio_iommu_type1.c               |  831 +++++++++++---
 include/linux/mdev.h                          |  177 +++
 include/linux/vfio.h                          |   30 +-
 include/uapi/linux/vfio.h                     |   10 +
 samples/vfio-mdev/Makefile                    |   13 +
 samples/vfio-mdev/mtty.c                      | 1503 +++++++++++++++++++++++++
 21 files changed, 4328 insertions(+), 236 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-vfio-mdev
 create mode 100644 Documentation/vfio-mediated-device.txt
 create mode 100644 drivers/vfio/mdev/Kconfig
 create mode 100644 drivers/vfio/mdev/Makefile
 create mode 100644 drivers/vfio/mdev/mdev_core.c
 create mode 100644 drivers/vfio/mdev/mdev_driver.c
 create mode 100644 drivers/vfio/mdev/mdev_private.h
 create mode 100644 drivers/vfio/mdev/mdev_sysfs.c
 create mode 100644 drivers/vfio/mdev/vfio_mdev.c
 create mode 100644 include/linux/mdev.h
 create mode 100644 samples/vfio-mdev/Makefile
 create mode 100644 samples/vfio-mdev/mtty.c

-- 
2.7.0

^ permalink raw reply

* [PATCH v12 01/22] vfio: Mediated device Core driver
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

Design for Mediated Device Driver:
Main purpose of this driver is to provide a common interface for mediated
device management that can be used by different drivers of different
devices.

This module provides a generic interface to create the device, add it to
mediated bus, add device to IOMMU group and then add it to vfio group.

Below is the high Level block diagram, with Nvidia, Intel and IBM devices
as example, since these are the devices which are going to actively use
this module as of now.

 +---------------+
 |               |
 | +-----------+ |  mdev_register_driver() +--------------+
 | |           | +<------------------------+ __init()     |
 | |  mdev     | |                         |              |
 | |  bus      | +------------------------>+              |<-> VFIO user
 | |  driver   | |     probe()/remove()    | vfio_mdev.ko |    APIs
 | |           | |                         |              |
 | +-----------+ |                         +--------------+
 |               |
 |  MDEV CORE    |
 |   MODULE      |
 |   mdev.ko     |
 | +-----------+ |  mdev_register_device() +--------------+
 | |           | +<------------------------+              |
 | |           | |                         |  nvidia.ko   |<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | | Physical  | |
 | |  device   | |  mdev_register_device() +--------------+
 | | interface | |<------------------------+              |
 | |           | |                         |  i915.ko     |<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | |           | |
 | |           | |  mdev_register_device() +--------------+
 | |           | +<------------------------+              |
 | |           | |                         | ccw_device.ko|<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | +-----------+ |
 +---------------+

Core driver provides two types of registration interfaces:
1. Registration interface for mediated bus driver:

/**
  * struct mdev_driver - Mediated device's driver
  * @name: driver name
  * @probe: called when new device created
  * @remove:called when device removed
  * @driver:device driver structure
  *
  **/
struct mdev_driver {
         const char *name;
         int  (*probe)  (struct device *dev);
         void (*remove) (struct device *dev);
         struct device_driver    driver;
};

Mediated bus driver for mdev device should use this interface to register
and unregister with core driver respectively:

int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
void mdev_unregister_driver(struct mdev_driver *drv);

Mediated bus driver is responsible to add/delete mediated devices to/from
VFIO group when devices are bound and unbound to the driver.

2. Physical device driver interface
This interface provides vendor driver the set APIs to manage physical
device related work in its driver. APIs are :

* dev_attr_groups: attributes of the parent device.
* mdev_attr_groups: attributes of the mediated device.
* supported_type_groups: attributes to define supported type. This is
			 mandatory field.
* create: to allocate basic resources in vendor driver for a mediated
         device. This is mandatory to be provided by vendor driver.
* remove: to free resources in vendor driver when mediated device is
         destroyed. This is mandatory to be provided by vendor driver.
* open: open callback of mediated device
* release: release callback of mediated device
* read : read emulation callback.
* write: write emulation callback.
* ioctl: ioctl callback.
* mmap: mmap emulation callback.

Drivers should use these interfaces to register and unregister device to
mdev core driver respectively:

extern int  mdev_register_device(struct device *dev,
                                 const struct parent_ops *ops);
extern void mdev_unregister_device(struct device *dev);

There are no locks to serialize above callbacks in mdev driver and
vfio_mdev driver. If required, vendor driver can have locks to serialize
above APIs in their driver.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>

Change-Id: I73a5084574270b14541c529461ea2f03c292d510
---
 drivers/vfio/Kconfig             |   1 +
 drivers/vfio/Makefile            |   1 +
 drivers/vfio/mdev/Kconfig        |   9 +
 drivers/vfio/mdev/Makefile       |   4 +
 drivers/vfio/mdev/mdev_core.c    | 374 +++++++++++++++++++++++++++++++++++++++
 drivers/vfio/mdev/mdev_driver.c  | 120 +++++++++++++
 drivers/vfio/mdev/mdev_private.h |  41 +++++
 drivers/vfio/mdev/mdev_sysfs.c   | 286 ++++++++++++++++++++++++++++++
 include/linux/mdev.h             | 168 ++++++++++++++++++
 9 files changed, 1004 insertions(+)
 create mode 100644 drivers/vfio/mdev/Kconfig
 create mode 100644 drivers/vfio/mdev/Makefile
 create mode 100644 drivers/vfio/mdev/mdev_core.c
 create mode 100644 drivers/vfio/mdev/mdev_driver.c
 create mode 100644 drivers/vfio/mdev/mdev_private.h
 create mode 100644 drivers/vfio/mdev/mdev_sysfs.c
 create mode 100644 include/linux/mdev.h

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index da6e2ce77495..23eced02aaf6 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -48,4 +48,5 @@ menuconfig VFIO_NOIOMMU
 
 source "drivers/vfio/pci/Kconfig"
 source "drivers/vfio/platform/Kconfig"
+source "drivers/vfio/mdev/Kconfig"
 source "virt/lib/Kconfig"
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 7b8a31f63fea..4a23c13b6be4 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
 obj-$(CONFIG_VFIO_PCI) += pci/
 obj-$(CONFIG_VFIO_PLATFORM) += platform/
+obj-$(CONFIG_VFIO_MDEV) += mdev/
diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
new file mode 100644
index 000000000000..258481d65ebd
--- /dev/null
+++ b/drivers/vfio/mdev/Kconfig
@@ -0,0 +1,9 @@
+
+config VFIO_MDEV
+	tristate "Mediated device driver framework"
+	depends on VFIO
+	default n
+	help
+	  Provides a framework to virtualize devices.
+
+	  If you don't know what do here, say N.
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
new file mode 100644
index 000000000000..31bc04801d94
--- /dev/null
+++ b/drivers/vfio/mdev/Makefile
@@ -0,0 +1,4 @@
+
+mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
+
+obj-$(CONFIG_VFIO_MDEV) += mdev.o
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
new file mode 100644
index 000000000000..613e8a8a3b2a
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -0,0 +1,374 @@
+/*
+ * Mediated device Core Driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/sysfs.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+#define DRIVER_VERSION		"0.1"
+#define DRIVER_AUTHOR		"NVIDIA Corporation"
+#define DRIVER_DESC		"Mediated device Core Driver"
+
+static LIST_HEAD(parent_list);
+static DEFINE_MUTEX(parent_list_lock);
+static struct class_compat *mdev_bus_compat_class;
+
+static int _find_mdev_device(struct device *dev, void *data)
+{
+	struct mdev_device *mdev;
+
+	if (!dev_is_mdev(dev))
+		return 0;
+
+	mdev = to_mdev_device(dev);
+
+	if (uuid_le_cmp(mdev->uuid, *(uuid_le *)data) == 0)
+		return 1;
+
+	return 0;
+}
+
+static bool mdev_device_exist(struct parent_device *parent, uuid_le uuid)
+{
+	struct device *dev;
+
+	dev = device_find_child(parent->dev, &uuid, _find_mdev_device);
+	if (dev) {
+		put_device(dev);
+		return true;
+	}
+
+	return false;
+}
+
+/* Should be called holding parent_list_lock */
+static struct parent_device *__find_parent_device(struct device *dev)
+{
+	struct parent_device *parent;
+
+	list_for_each_entry(parent, &parent_list, next) {
+		if (parent->dev == dev)
+			return parent;
+	}
+	return NULL;
+}
+
+static void mdev_release_parent(struct kref *kref)
+{
+	struct parent_device *parent = container_of(kref, struct parent_device,
+						    ref);
+	struct device *dev = parent->dev;
+
+	kfree(parent);
+	put_device(dev);
+}
+
+static
+inline struct parent_device *mdev_get_parent(struct parent_device *parent)
+{
+	if (parent)
+		kref_get(&parent->ref);
+
+	return parent;
+}
+
+static inline void mdev_put_parent(struct parent_device *parent)
+{
+	if (parent)
+		kref_put(&parent->ref, mdev_release_parent);
+}
+
+static int mdev_device_create_ops(struct kobject *kobj,
+				  struct mdev_device *mdev)
+{
+	struct parent_device *parent = mdev->parent;
+	int ret;
+
+	ret = parent->ops->create(kobj, mdev);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_groups(&mdev->dev.kobj,
+				  parent->ops->mdev_attr_groups);
+	if (ret)
+		parent->ops->remove(mdev);
+
+	return ret;
+}
+
+/*
+ * mdev_device_remove_ops gets called from sysfs's 'remove' and when parent
+ * device is being unregistered from mdev device framework.
+ * - 'force_remove' is set to 'false' when called from sysfs's 'remove' which
+ *   indicates that if the mdev device is active, used by VMM or userspace
+ *   application, vendor driver could return error then don't remove the device.
+ * - 'force_remove' is set to 'true' when called from mdev_unregister_device()
+ *   which indicate that parent device is being removed from mdev device
+ *   framework so remove mdev device forcefully.
+ */
+static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove)
+{
+	struct parent_device *parent = mdev->parent;
+	int ret;
+
+	/*
+	 * Vendor driver can return error if VMM or userspace application is
+	 * using this mdev device.
+	 */
+	ret = parent->ops->remove(mdev);
+	if (ret && !force_remove)
+		return -EBUSY;
+
+	sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups);
+	return 0;
+}
+
+static int mdev_device_remove_cb(struct device *dev, void *data)
+{
+	if (!dev_is_mdev(dev))
+		return 0;
+
+	return mdev_device_remove(dev, data ? *(bool *)data : true);
+}
+
+/*
+ * mdev_register_device : Register a device
+ * @dev: device structure representing parent device.
+ * @ops: Parent device operation structure to be registered.
+ *
+ * Add device to list of registered parent devices.
+ * Returns a negative value on error, otherwise 0.
+ */
+int mdev_register_device(struct device *dev, const struct parent_ops *ops)
+{
+	int ret;
+	struct parent_device *parent;
+
+	/* check for mandatory ops */
+	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
+		return -EINVAL;
+
+	dev = get_device(dev);
+	if (!dev)
+		return -EINVAL;
+
+	mutex_lock(&parent_list_lock);
+
+	/* Check for duplicate */
+	parent = __find_parent_device(dev);
+	if (parent) {
+		ret = -EEXIST;
+		goto add_dev_err;
+	}
+
+	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	if (!parent) {
+		ret = -ENOMEM;
+		goto add_dev_err;
+	}
+
+	kref_init(&parent->ref);
+	mutex_init(&parent->lock);
+
+	parent->dev = dev;
+	parent->ops = ops;
+
+	if (!mdev_bus_compat_class) {
+		mdev_bus_compat_class = class_compat_register("mdev_bus");
+		if (!mdev_bus_compat_class) {
+			ret = -ENOMEM;
+			goto add_dev_err;
+		}
+	}
+
+	ret = parent_create_sysfs_files(parent);
+	if (ret)
+		goto add_dev_err;
+
+	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
+	if (ret)
+		dev_warn(dev, "Failed to create compatibility class link\n");
+
+	list_add(&parent->next, &parent_list);
+	mutex_unlock(&parent_list_lock);
+
+	dev_info(dev, "MDEV: Registered\n");
+	return 0;
+
+add_dev_err:
+	mutex_unlock(&parent_list_lock);
+	if (parent)
+		mdev_put_parent(parent);
+	else
+		put_device(dev);
+	return ret;
+}
+EXPORT_SYMBOL(mdev_register_device);
+
+/*
+ * mdev_unregister_device : Unregister a parent device
+ * @dev: device structure representing parent device.
+ *
+ * Remove device from list of registered parent devices. Give a chance to free
+ * existing mediated devices for given device.
+ */
+
+void mdev_unregister_device(struct device *dev)
+{
+	struct parent_device *parent;
+	bool force_remove = true;
+
+	mutex_lock(&parent_list_lock);
+	parent = __find_parent_device(dev);
+
+	if (!parent) {
+		mutex_unlock(&parent_list_lock);
+		return;
+	}
+	dev_info(dev, "MDEV: Unregistering\n");
+
+	list_del(&parent->next);
+	class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
+
+	device_for_each_child(dev, (void *)&force_remove,
+			      mdev_device_remove_cb);
+
+	parent_remove_sysfs_files(parent);
+
+	mutex_unlock(&parent_list_lock);
+	mdev_put_parent(parent);
+}
+EXPORT_SYMBOL(mdev_unregister_device);
+
+static void mdev_device_release(struct device *dev)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+
+	dev_dbg(&mdev->dev, "MDEV: destroying\n");
+	kfree(mdev);
+}
+
+int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
+{
+	int ret;
+	struct mdev_device *mdev;
+	struct parent_device *parent;
+	struct mdev_type *type = to_mdev_type(kobj);
+
+	parent = mdev_get_parent(type->parent);
+	if (!parent)
+		return -EINVAL;
+
+	mutex_lock(&parent->lock);
+
+	/* Check for duplicate */
+	if (mdev_device_exist(parent, uuid)) {
+		ret = -EEXIST;
+		goto create_err;
+	}
+
+	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+	if (!mdev) {
+		ret = -ENOMEM;
+		goto create_err;
+	}
+
+	memcpy(&mdev->uuid, &uuid, sizeof(uuid_le));
+	mdev->parent = parent;
+	kref_init(&mdev->ref);
+
+	mdev->dev.parent  = dev;
+	mdev->dev.bus     = &mdev_bus_type;
+	mdev->dev.release = mdev_device_release;
+	dev_set_name(&mdev->dev, "%pUl", uuid.b);
+
+	ret = device_register(&mdev->dev);
+	if (ret) {
+		put_device(&mdev->dev);
+		goto create_err;
+	}
+
+	ret = mdev_device_create_ops(kobj, mdev);
+	if (ret)
+		goto create_failed;
+
+	ret = mdev_create_sysfs_files(&mdev->dev, type);
+	if (ret) {
+		mdev_device_remove_ops(mdev, true);
+		goto create_failed;
+	}
+
+	mdev->type_kobj = kobj;
+	dev_dbg(&mdev->dev, "MDEV: created\n");
+
+	mutex_unlock(&parent->lock);
+	return ret;
+
+create_failed:
+	device_unregister(&mdev->dev);
+
+create_err:
+	mutex_unlock(&parent->lock);
+	mdev_put_parent(parent);
+	return ret;
+}
+
+int mdev_device_remove(struct device *dev, bool force_remove)
+{
+	struct mdev_device *mdev;
+	struct parent_device *parent;
+	struct mdev_type *type;
+	int ret;
+
+	mdev = to_mdev_device(dev);
+	type = to_mdev_type(mdev->type_kobj);
+	parent = mdev->parent;
+	mutex_lock(&parent->lock);
+
+	ret = mdev_device_remove_ops(mdev, force_remove);
+	if (ret) {
+		mutex_unlock(&parent->lock);
+		return ret;
+	}
+
+	mdev_remove_sysfs_files(dev, type);
+	device_unregister(dev);
+	mutex_unlock(&parent->lock);
+	mdev_put_parent(parent);
+	return ret;
+}
+
+static int __init mdev_init(void)
+{
+	return mdev_bus_register();
+}
+
+static void __exit mdev_exit(void)
+{
+	if (mdev_bus_compat_class)
+		class_compat_unregister(mdev_bus_compat_class);
+
+	mdev_bus_unregister();
+}
+
+module_init(mdev_init)
+module_exit(mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
new file mode 100644
index 000000000000..6c19a2f6b5a2
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -0,0 +1,120 @@
+/*
+ * MDEV driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/iommu.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+static int mdev_attach_iommu(struct mdev_device *mdev)
+{
+	int ret;
+	struct iommu_group *group;
+
+	group = iommu_group_alloc();
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = iommu_group_add_device(group, &mdev->dev);
+	if (ret)
+		goto attach_fail;
+
+	dev_info(&mdev->dev, "MDEV: group_id = %d\n", iommu_group_id(group));
+attach_fail:
+	iommu_group_put(group);
+	return ret;
+}
+
+static void mdev_detach_iommu(struct mdev_device *mdev)
+{
+	iommu_group_remove_device(&mdev->dev);
+	dev_info(&mdev->dev, "MDEV: detaching iommu\n");
+}
+
+static int mdev_probe(struct device *dev)
+{
+	struct mdev_driver *drv = to_mdev_driver(dev->driver);
+	struct mdev_device *mdev = to_mdev_device(dev);
+	int ret;
+
+	ret = mdev_attach_iommu(mdev);
+	if (ret)
+		return ret;
+
+	if (drv && drv->probe) {
+		ret = drv->probe(dev);
+		if (ret)
+			mdev_detach_iommu(mdev);
+	}
+
+	return ret;
+}
+
+static int mdev_remove(struct device *dev)
+{
+	struct mdev_driver *drv = to_mdev_driver(dev->driver);
+	struct mdev_device *mdev = to_mdev_device(dev);
+
+	if (drv && drv->remove)
+		drv->remove(dev);
+
+	mdev_detach_iommu(mdev);
+
+	return 0;
+}
+
+struct bus_type mdev_bus_type = {
+	.name		= "mdev",
+	.probe		= mdev_probe,
+	.remove		= mdev_remove,
+};
+EXPORT_SYMBOL_GPL(mdev_bus_type);
+
+/**
+ * mdev_register_driver - register a new MDEV driver
+ * @drv: the driver to register
+ * @owner: module owner of driver to be registered
+ *
+ * Returns a negative value on error, otherwise 0.
+ **/
+int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
+{
+	/* initialize common driver fields */
+	drv->driver.name = drv->name;
+	drv->driver.bus = &mdev_bus_type;
+	drv->driver.owner = owner;
+
+	/* register with core */
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_register_driver);
+
+/*
+ * mdev_unregister_driver - unregister MDEV driver
+ * @drv: the driver to unregister
+ */
+void mdev_unregister_driver(struct mdev_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_unregister_driver);
+
+int mdev_bus_register(void)
+{
+	return bus_register(&mdev_bus_type);
+}
+
+void mdev_bus_unregister(void)
+{
+	bus_unregister(&mdev_bus_type);
+}
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
new file mode 100644
index 000000000000..d35097cbf3d7
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -0,0 +1,41 @@
+/*
+ * Mediated device interal definitions
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#ifndef MDEV_PRIVATE_H
+#define MDEV_PRIVATE_H
+
+int  mdev_bus_register(void);
+void mdev_bus_unregister(void);
+
+struct mdev_type {
+	struct kobject kobj;
+	struct kobject *devices_kobj;
+	struct parent_device *parent;
+	struct list_head next;
+	struct attribute_group *group;
+};
+
+#define to_mdev_type_attr(_attr)	\
+	container_of(_attr, struct mdev_type_attribute, attr)
+#define to_mdev_type(_kobj)		\
+	container_of(_kobj, struct mdev_type, kobj)
+
+int  parent_create_sysfs_files(struct parent_device *parent);
+void parent_remove_sysfs_files(struct parent_device *parent);
+
+int  mdev_create_sysfs_files(struct device *dev, struct mdev_type *type);
+void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type);
+
+int  mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid);
+int  mdev_device_remove(struct device *dev, bool force_remove);
+
+#endif /* MDEV_PRIVATE_H */
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
new file mode 100644
index 000000000000..04f9b2925e6d
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -0,0 +1,286 @@
+/*
+ * File attributes for Mediated devices
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/sysfs.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+/* Static functions */
+
+static ssize_t mdev_type_attr_show(struct kobject *kobj,
+				     struct attribute *__attr, char *buf)
+{
+	struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
+	struct mdev_type *type = to_mdev_type(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->show)
+		ret = attr->show(kobj, type->parent->dev, buf);
+	return ret;
+}
+
+static ssize_t mdev_type_attr_store(struct kobject *kobj,
+				      struct attribute *__attr,
+				      const char *buf, size_t count)
+{
+	struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
+	struct mdev_type *type = to_mdev_type(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->store)
+		ret = attr->store(&type->kobj, type->parent->dev, buf, count);
+	return ret;
+}
+
+static const struct sysfs_ops mdev_type_sysfs_ops = {
+	.show = mdev_type_attr_show,
+	.store = mdev_type_attr_store,
+};
+
+static ssize_t create_store(struct kobject *kobj, struct device *dev,
+			    const char *buf, size_t count)
+{
+	char *str;
+	uuid_le uuid;
+	int ret;
+
+	if ((count < UUID_STRING_LEN) || (count > UUID_STRING_LEN + 1))
+		return -EINVAL;
+
+	str = kstrndup(buf, count, GFP_KERNEL);
+	if (!str)
+		return -ENOMEM;
+
+	ret = uuid_le_to_bin(str, &uuid);
+	kfree(str);
+	if (ret)
+		return ret;
+
+	ret = mdev_device_create(kobj, dev, uuid);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+MDEV_TYPE_ATTR_WO(create);
+
+static void mdev_type_release(struct kobject *kobj)
+{
+	struct mdev_type *type = to_mdev_type(kobj);
+
+	pr_debug("Releasing group %s\n", kobj->name);
+	kfree(type);
+}
+
+static struct kobj_type mdev_type_ktype = {
+	.sysfs_ops = &mdev_type_sysfs_ops,
+	.release = mdev_type_release,
+};
+
+struct mdev_type *add_mdev_supported_type(struct parent_device *parent,
+					  struct attribute_group *group)
+{
+	struct mdev_type *type;
+	int ret;
+
+	if (!group->name) {
+		pr_err("%s: Type name empty!\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	type = kzalloc(sizeof(*type), GFP_KERNEL);
+	if (!type)
+		return ERR_PTR(-ENOMEM);
+
+	type->kobj.kset = parent->mdev_types_kset;
+
+	ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
+				   "%s-%s", dev_driver_string(parent->dev),
+				   group->name);
+	if (ret) {
+		kfree(type);
+		return ERR_PTR(ret);
+	}
+
+	ret = sysfs_create_file(&type->kobj, &mdev_type_attr_create.attr);
+	if (ret)
+		goto attr_create_failed;
+
+	type->devices_kobj = kobject_create_and_add("devices", &type->kobj);
+	if (!type->devices_kobj) {
+		ret = -ENOMEM;
+		goto attr_devices_failed;
+	}
+
+	ret = sysfs_create_files(&type->kobj,
+				 (const struct attribute **)group->attrs);
+	if (ret) {
+		ret = -ENOMEM;
+		goto attrs_failed;
+	}
+
+	type->group = group;
+	type->parent = parent;
+	return type;
+
+attrs_failed:
+	kobject_put(type->devices_kobj);
+attr_devices_failed:
+	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
+attr_create_failed:
+	kobject_del(&type->kobj);
+	kobject_put(&type->kobj);
+	return ERR_PTR(ret);
+}
+
+static void remove_mdev_supported_type(struct mdev_type *type)
+{
+	sysfs_remove_files(&type->kobj,
+			   (const struct attribute **)type->group->attrs);
+	kobject_put(type->devices_kobj);
+	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
+	kobject_del(&type->kobj);
+	kobject_put(&type->kobj);
+}
+
+static int add_mdev_supported_type_groups(struct parent_device *parent)
+{
+	int i;
+
+	for (i = 0; parent->ops->supported_type_groups[i]; i++) {
+		struct mdev_type *type;
+
+		type = add_mdev_supported_type(parent,
+					parent->ops->supported_type_groups[i]);
+		if (IS_ERR(type)) {
+			struct mdev_type *ltype, *tmp;
+
+			list_for_each_entry_safe(ltype, tmp, &parent->type_list,
+						  next) {
+				list_del(&ltype->next);
+				remove_mdev_supported_type(ltype);
+			}
+			return PTR_ERR(type);
+		}
+		list_add(&type->next, &parent->type_list);
+	}
+	return 0;
+}
+
+/* mdev sysfs Functions */
+void parent_remove_sysfs_files(struct parent_device *parent)
+{
+	struct mdev_type *type, *tmp;
+
+	list_for_each_entry_safe(type, tmp, &parent->type_list, next) {
+		list_del(&type->next);
+		remove_mdev_supported_type(type);
+	}
+
+	sysfs_remove_groups(&parent->dev->kobj, parent->ops->dev_attr_groups);
+	kset_unregister(parent->mdev_types_kset);
+}
+
+int parent_create_sysfs_files(struct parent_device *parent)
+{
+	int ret;
+
+	parent->mdev_types_kset = kset_create_and_add("mdev_supported_types",
+					       NULL, &parent->dev->kobj);
+
+	if (!parent->mdev_types_kset)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&parent->type_list);
+
+	ret = sysfs_create_groups(&parent->dev->kobj,
+				  parent->ops->dev_attr_groups);
+	if (ret)
+		goto create_err;
+
+	ret = add_mdev_supported_type_groups(parent);
+	if (ret)
+		sysfs_remove_groups(&parent->dev->kobj,
+				    parent->ops->dev_attr_groups);
+	else
+		return ret;
+
+create_err:
+	kset_unregister(parent->mdev_types_kset);
+	return ret;
+}
+
+static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val && device_remove_file_self(dev, attr)) {
+		int ret;
+
+		ret = mdev_device_remove(dev, false);
+		if (ret) {
+			device_create_file(dev, attr);
+			return ret;
+		}
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(remove);
+
+static const struct attribute *mdev_device_attrs[] = {
+	&dev_attr_remove.attr,
+	NULL,
+};
+
+int  mdev_create_sysfs_files(struct device *dev, struct mdev_type *type)
+{
+	int ret;
+
+	ret = sysfs_create_files(&dev->kobj, mdev_device_attrs);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_link(type->devices_kobj, &dev->kobj, dev_name(dev));
+	if (ret)
+		goto device_link_failed;
+
+	ret = sysfs_create_link(&dev->kobj, &type->kobj, "mdev_type");
+	if (ret)
+		goto type_link_failed;
+
+	return ret;
+
+type_link_failed:
+	sysfs_remove_link(type->devices_kobj, dev_name(dev));
+device_link_failed:
+	sysfs_remove_files(&dev->kobj, mdev_device_attrs);
+	return ret;
+}
+
+void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type)
+{
+	sysfs_remove_link(&dev->kobj, "mdev_type");
+	sysfs_remove_link(type->devices_kobj, dev_name(dev));
+	sysfs_remove_files(&dev->kobj, mdev_device_attrs);
+}
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
new file mode 100644
index 000000000000..4900cc472364
--- /dev/null
+++ b/include/linux/mdev.h
@@ -0,0 +1,168 @@
+/*
+ * Mediated device definition
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#ifndef MDEV_H
+#define MDEV_H
+
+/* Parent Device */
+struct parent_device {
+	struct device		*dev;
+	const struct parent_ops	*ops;
+
+	/* internal */
+	struct kref		ref;
+	struct mutex		lock;
+	struct list_head	next;
+	struct kset		*mdev_types_kset;
+	struct list_head	type_list;
+};
+
+/* Mediated device */
+struct mdev_device {
+	struct device		dev;
+	struct parent_device	*parent;
+	uuid_le			uuid;
+	void			*driver_data;
+
+	/* internal */
+	struct kref		ref;
+	struct list_head	next;
+	struct kobject		*type_kobj;
+};
+
+/**
+ * struct parent_ops - Structure to be registered for each parent device to
+ * register the device to mdev module.
+ *
+ * @owner:		The module owner.
+ * @dev_attr_groups:	Attributes of the parent device.
+ * @mdev_attr_groups:	Attributes of the mediated device.
+ * @supported_type_groups: Attributes to define supported types. It is mandatory
+ *			to provide supported types.
+ * @create:		Called to allocate basic resources in parent device's
+ *			driver for a particular mediated device. It is
+ *			mandatory to provide create ops.
+ *			@kobj: kobject of type for which 'create' is called.
+ *			@mdev: mdev_device structure on of mediated device
+ *			      that is being created
+ *			Returns integer: success (0) or error (< 0)
+ * @remove:		Called to free resources in parent device's driver for a
+ *			a mediated device. It is mandatory to provide 'remove'
+ *			ops.
+ *			@mdev: mdev_device device structure which is being
+ *			       destroyed
+ *			Returns integer: success (0) or error (< 0)
+ * @open:		Open mediated device.
+ *			@mdev: mediated device.
+ *			Returns integer: success (0) or error (< 0)
+ * @release:		release mediated device
+ *			@mdev: mediated device.
+ * @read:		Read emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: read buffer
+ *			@count: number of bytes to read
+ *			@ppos: address.
+ *			Retuns number on bytes read on success or error.
+ * @write:		Write emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: write buffer
+ *			@count: number of bytes to be written
+ *			@ppos: address.
+ *			Retuns number on bytes written on success or error.
+ * @ioctl:		IOCTL callback
+ *			@mdev: mediated device structure
+ *			@cmd: ioctl command
+ *			@arg: arguments to ioctl
+ * @mmap:		mmap callback
+ *			@mdev: mediated device structure
+ *			@vma: vma structure
+ * Parent device that support mediated device should be registered with mdev
+ * module with parent_ops structure.
+ **/
+
+struct parent_ops {
+	struct module   *owner;
+	const struct attribute_group **dev_attr_groups;
+	const struct attribute_group **mdev_attr_groups;
+	struct attribute_group **supported_type_groups;
+
+	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
+	int     (*remove)(struct mdev_device *mdev);
+	int     (*open)(struct mdev_device *mdev);
+	void    (*release)(struct mdev_device *mdev);
+	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
+			size_t count, loff_t *ppos);
+	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
+			 size_t count, loff_t *ppos);
+	ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
+			 unsigned long arg);
+	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+};
+
+/* interface for exporting mdev supported type attributes */
+struct mdev_type_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
+	ssize_t (*store)(struct kobject *kobj, struct device *dev,
+			 const char *buf, size_t count);
+};
+
+#define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
+struct mdev_type_attribute mdev_type_attr_##_name =		\
+	__ATTR(_name, _mode, _show, _store)
+#define MDEV_TYPE_ATTR_RW(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
+#define MDEV_TYPE_ATTR_RO(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
+#define MDEV_TYPE_ATTR_WO(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
+
+/**
+ * struct mdev_driver - Mediated device driver
+ * @name: driver name
+ * @probe: called when new device created
+ * @remove: called when device removed
+ * @driver: device driver structure
+ *
+ **/
+struct mdev_driver {
+	const char *name;
+	int  (*probe)(struct device *dev);
+	void (*remove)(struct device *dev);
+	struct device_driver driver;
+};
+
+#define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
+#define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
+
+static inline void *mdev_get_drvdata(struct mdev_device *mdev)
+{
+	return mdev->driver_data;
+}
+
+static inline void mdev_set_drvdata(struct mdev_device *mdev, void *data)
+{
+	mdev->driver_data = data;
+}
+
+extern struct bus_type mdev_bus_type;
+
+#define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)
+
+extern int  mdev_register_device(struct device *dev,
+				 const struct parent_ops *ops);
+extern void mdev_unregister_device(struct device *dev);
+
+extern int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
+extern void mdev_unregister_driver(struct mdev_driver *drv);
+
+#endif /* MDEV_H */
-- 
2.7.0


^ permalink raw reply related

* [PATCH v12 03/22] vfio: Rearrange functions to get vfio_group from dev
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

This patch rearranges functions to get vfio_group from device

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>

Change-Id: I1f93262bdbab75094bc24b087b29da35ba70c4c6
---
 drivers/vfio/vfio.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index d1d70e0b011b..23bc86c1d05d 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -480,6 +480,21 @@ static struct vfio_group *vfio_group_get_from_minor(int minor)
 	return group;
 }
 
+static struct vfio_group *vfio_group_get_from_dev(struct device *dev)
+{
+	struct iommu_group *iommu_group;
+	struct vfio_group *group;
+
+	iommu_group = iommu_group_get(dev);
+	if (!iommu_group)
+		return NULL;
+
+	group = vfio_group_get_from_iommu(iommu_group);
+	iommu_group_put(iommu_group);
+
+	return group;
+}
+
 /**
  * Device objects - create, release, get, put, search
  */
@@ -811,16 +826,10 @@ EXPORT_SYMBOL_GPL(vfio_add_group_dev);
  */
 struct vfio_device *vfio_device_get_from_dev(struct device *dev)
 {
-	struct iommu_group *iommu_group;
 	struct vfio_group *group;
 	struct vfio_device *device;
 
-	iommu_group = iommu_group_get(dev);
-	if (!iommu_group)
-		return NULL;
-
-	group = vfio_group_get_from_iommu(iommu_group);
-	iommu_group_put(iommu_group);
+	group = vfio_group_get_from_dev(dev);
 	if (!group)
 		return NULL;
 
-- 
2.7.0


^ permalink raw reply related

* [Qemu-devel] [PATCH v12 01/22] vfio: Mediated device Core driver
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

Design for Mediated Device Driver:
Main purpose of this driver is to provide a common interface for mediated
device management that can be used by different drivers of different
devices.

This module provides a generic interface to create the device, add it to
mediated bus, add device to IOMMU group and then add it to vfio group.

Below is the high Level block diagram, with Nvidia, Intel and IBM devices
as example, since these are the devices which are going to actively use
this module as of now.

 +---------------+
 |               |
 | +-----------+ |  mdev_register_driver() +--------------+
 | |           | +<------------------------+ __init()     |
 | |  mdev     | |                         |              |
 | |  bus      | +------------------------>+              |<-> VFIO user
 | |  driver   | |     probe()/remove()    | vfio_mdev.ko |    APIs
 | |           | |                         |              |
 | +-----------+ |                         +--------------+
 |               |
 |  MDEV CORE    |
 |   MODULE      |
 |   mdev.ko     |
 | +-----------+ |  mdev_register_device() +--------------+
 | |           | +<------------------------+              |
 | |           | |                         |  nvidia.ko   |<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | | Physical  | |
 | |  device   | |  mdev_register_device() +--------------+
 | | interface | |<------------------------+              |
 | |           | |                         |  i915.ko     |<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | |           | |
 | |           | |  mdev_register_device() +--------------+
 | |           | +<------------------------+              |
 | |           | |                         | ccw_device.ko|<-> physical
 | |           | +------------------------>+              |    device
 | |           | |        callback         +--------------+
 | +-----------+ |
 +---------------+

Core driver provides two types of registration interfaces:
1. Registration interface for mediated bus driver:

/**
  * struct mdev_driver - Mediated device's driver
  * @name: driver name
  * @probe: called when new device created
  * @remove:called when device removed
  * @driver:device driver structure
  *
  **/
struct mdev_driver {
         const char *name;
         int  (*probe)  (struct device *dev);
         void (*remove) (struct device *dev);
         struct device_driver    driver;
};

Mediated bus driver for mdev device should use this interface to register
and unregister with core driver respectively:

int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
void mdev_unregister_driver(struct mdev_driver *drv);

Mediated bus driver is responsible to add/delete mediated devices to/from
VFIO group when devices are bound and unbound to the driver.

2. Physical device driver interface
This interface provides vendor driver the set APIs to manage physical
device related work in its driver. APIs are :

* dev_attr_groups: attributes of the parent device.
* mdev_attr_groups: attributes of the mediated device.
* supported_type_groups: attributes to define supported type. This is
			 mandatory field.
* create: to allocate basic resources in vendor driver for a mediated
         device. This is mandatory to be provided by vendor driver.
* remove: to free resources in vendor driver when mediated device is
         destroyed. This is mandatory to be provided by vendor driver.
* open: open callback of mediated device
* release: release callback of mediated device
* read : read emulation callback.
* write: write emulation callback.
* ioctl: ioctl callback.
* mmap: mmap emulation callback.

Drivers should use these interfaces to register and unregister device to
mdev core driver respectively:

extern int  mdev_register_device(struct device *dev,
                                 const struct parent_ops *ops);
extern void mdev_unregister_device(struct device *dev);

There are no locks to serialize above callbacks in mdev driver and
vfio_mdev driver. If required, vendor driver can have locks to serialize
above APIs in their driver.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>

Change-Id: I73a5084574270b14541c529461ea2f03c292d510
---
 drivers/vfio/Kconfig             |   1 +
 drivers/vfio/Makefile            |   1 +
 drivers/vfio/mdev/Kconfig        |   9 +
 drivers/vfio/mdev/Makefile       |   4 +
 drivers/vfio/mdev/mdev_core.c    | 374 +++++++++++++++++++++++++++++++++++++++
 drivers/vfio/mdev/mdev_driver.c  | 120 +++++++++++++
 drivers/vfio/mdev/mdev_private.h |  41 +++++
 drivers/vfio/mdev/mdev_sysfs.c   | 286 ++++++++++++++++++++++++++++++
 include/linux/mdev.h             | 168 ++++++++++++++++++
 9 files changed, 1004 insertions(+)
 create mode 100644 drivers/vfio/mdev/Kconfig
 create mode 100644 drivers/vfio/mdev/Makefile
 create mode 100644 drivers/vfio/mdev/mdev_core.c
 create mode 100644 drivers/vfio/mdev/mdev_driver.c
 create mode 100644 drivers/vfio/mdev/mdev_private.h
 create mode 100644 drivers/vfio/mdev/mdev_sysfs.c
 create mode 100644 include/linux/mdev.h

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index da6e2ce77495..23eced02aaf6 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -48,4 +48,5 @@ menuconfig VFIO_NOIOMMU
 
 source "drivers/vfio/pci/Kconfig"
 source "drivers/vfio/platform/Kconfig"
+source "drivers/vfio/mdev/Kconfig"
 source "virt/lib/Kconfig"
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 7b8a31f63fea..4a23c13b6be4 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
 obj-$(CONFIG_VFIO_PCI) += pci/
 obj-$(CONFIG_VFIO_PLATFORM) += platform/
+obj-$(CONFIG_VFIO_MDEV) += mdev/
diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
new file mode 100644
index 000000000000..258481d65ebd
--- /dev/null
+++ b/drivers/vfio/mdev/Kconfig
@@ -0,0 +1,9 @@
+
+config VFIO_MDEV
+	tristate "Mediated device driver framework"
+	depends on VFIO
+	default n
+	help
+	  Provides a framework to virtualize devices.
+
+	  If you don't know what do here, say N.
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
new file mode 100644
index 000000000000..31bc04801d94
--- /dev/null
+++ b/drivers/vfio/mdev/Makefile
@@ -0,0 +1,4 @@
+
+mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
+
+obj-$(CONFIG_VFIO_MDEV) += mdev.o
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
new file mode 100644
index 000000000000..613e8a8a3b2a
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -0,0 +1,374 @@
+/*
+ * Mediated device Core Driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/sysfs.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+#define DRIVER_VERSION		"0.1"
+#define DRIVER_AUTHOR		"NVIDIA Corporation"
+#define DRIVER_DESC		"Mediated device Core Driver"
+
+static LIST_HEAD(parent_list);
+static DEFINE_MUTEX(parent_list_lock);
+static struct class_compat *mdev_bus_compat_class;
+
+static int _find_mdev_device(struct device *dev, void *data)
+{
+	struct mdev_device *mdev;
+
+	if (!dev_is_mdev(dev))
+		return 0;
+
+	mdev = to_mdev_device(dev);
+
+	if (uuid_le_cmp(mdev->uuid, *(uuid_le *)data) == 0)
+		return 1;
+
+	return 0;
+}
+
+static bool mdev_device_exist(struct parent_device *parent, uuid_le uuid)
+{
+	struct device *dev;
+
+	dev = device_find_child(parent->dev, &uuid, _find_mdev_device);
+	if (dev) {
+		put_device(dev);
+		return true;
+	}
+
+	return false;
+}
+
+/* Should be called holding parent_list_lock */
+static struct parent_device *__find_parent_device(struct device *dev)
+{
+	struct parent_device *parent;
+
+	list_for_each_entry(parent, &parent_list, next) {
+		if (parent->dev == dev)
+			return parent;
+	}
+	return NULL;
+}
+
+static void mdev_release_parent(struct kref *kref)
+{
+	struct parent_device *parent = container_of(kref, struct parent_device,
+						    ref);
+	struct device *dev = parent->dev;
+
+	kfree(parent);
+	put_device(dev);
+}
+
+static
+inline struct parent_device *mdev_get_parent(struct parent_device *parent)
+{
+	if (parent)
+		kref_get(&parent->ref);
+
+	return parent;
+}
+
+static inline void mdev_put_parent(struct parent_device *parent)
+{
+	if (parent)
+		kref_put(&parent->ref, mdev_release_parent);
+}
+
+static int mdev_device_create_ops(struct kobject *kobj,
+				  struct mdev_device *mdev)
+{
+	struct parent_device *parent = mdev->parent;
+	int ret;
+
+	ret = parent->ops->create(kobj, mdev);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_groups(&mdev->dev.kobj,
+				  parent->ops->mdev_attr_groups);
+	if (ret)
+		parent->ops->remove(mdev);
+
+	return ret;
+}
+
+/*
+ * mdev_device_remove_ops gets called from sysfs's 'remove' and when parent
+ * device is being unregistered from mdev device framework.
+ * - 'force_remove' is set to 'false' when called from sysfs's 'remove' which
+ *   indicates that if the mdev device is active, used by VMM or userspace
+ *   application, vendor driver could return error then don't remove the device.
+ * - 'force_remove' is set to 'true' when called from mdev_unregister_device()
+ *   which indicate that parent device is being removed from mdev device
+ *   framework so remove mdev device forcefully.
+ */
+static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove)
+{
+	struct parent_device *parent = mdev->parent;
+	int ret;
+
+	/*
+	 * Vendor driver can return error if VMM or userspace application is
+	 * using this mdev device.
+	 */
+	ret = parent->ops->remove(mdev);
+	if (ret && !force_remove)
+		return -EBUSY;
+
+	sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups);
+	return 0;
+}
+
+static int mdev_device_remove_cb(struct device *dev, void *data)
+{
+	if (!dev_is_mdev(dev))
+		return 0;
+
+	return mdev_device_remove(dev, data ? *(bool *)data : true);
+}
+
+/*
+ * mdev_register_device : Register a device
+ * @dev: device structure representing parent device.
+ * @ops: Parent device operation structure to be registered.
+ *
+ * Add device to list of registered parent devices.
+ * Returns a negative value on error, otherwise 0.
+ */
+int mdev_register_device(struct device *dev, const struct parent_ops *ops)
+{
+	int ret;
+	struct parent_device *parent;
+
+	/* check for mandatory ops */
+	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
+		return -EINVAL;
+
+	dev = get_device(dev);
+	if (!dev)
+		return -EINVAL;
+
+	mutex_lock(&parent_list_lock);
+
+	/* Check for duplicate */
+	parent = __find_parent_device(dev);
+	if (parent) {
+		ret = -EEXIST;
+		goto add_dev_err;
+	}
+
+	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	if (!parent) {
+		ret = -ENOMEM;
+		goto add_dev_err;
+	}
+
+	kref_init(&parent->ref);
+	mutex_init(&parent->lock);
+
+	parent->dev = dev;
+	parent->ops = ops;
+
+	if (!mdev_bus_compat_class) {
+		mdev_bus_compat_class = class_compat_register("mdev_bus");
+		if (!mdev_bus_compat_class) {
+			ret = -ENOMEM;
+			goto add_dev_err;
+		}
+	}
+
+	ret = parent_create_sysfs_files(parent);
+	if (ret)
+		goto add_dev_err;
+
+	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
+	if (ret)
+		dev_warn(dev, "Failed to create compatibility class link\n");
+
+	list_add(&parent->next, &parent_list);
+	mutex_unlock(&parent_list_lock);
+
+	dev_info(dev, "MDEV: Registered\n");
+	return 0;
+
+add_dev_err:
+	mutex_unlock(&parent_list_lock);
+	if (parent)
+		mdev_put_parent(parent);
+	else
+		put_device(dev);
+	return ret;
+}
+EXPORT_SYMBOL(mdev_register_device);
+
+/*
+ * mdev_unregister_device : Unregister a parent device
+ * @dev: device structure representing parent device.
+ *
+ * Remove device from list of registered parent devices. Give a chance to free
+ * existing mediated devices for given device.
+ */
+
+void mdev_unregister_device(struct device *dev)
+{
+	struct parent_device *parent;
+	bool force_remove = true;
+
+	mutex_lock(&parent_list_lock);
+	parent = __find_parent_device(dev);
+
+	if (!parent) {
+		mutex_unlock(&parent_list_lock);
+		return;
+	}
+	dev_info(dev, "MDEV: Unregistering\n");
+
+	list_del(&parent->next);
+	class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
+
+	device_for_each_child(dev, (void *)&force_remove,
+			      mdev_device_remove_cb);
+
+	parent_remove_sysfs_files(parent);
+
+	mutex_unlock(&parent_list_lock);
+	mdev_put_parent(parent);
+}
+EXPORT_SYMBOL(mdev_unregister_device);
+
+static void mdev_device_release(struct device *dev)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+
+	dev_dbg(&mdev->dev, "MDEV: destroying\n");
+	kfree(mdev);
+}
+
+int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
+{
+	int ret;
+	struct mdev_device *mdev;
+	struct parent_device *parent;
+	struct mdev_type *type = to_mdev_type(kobj);
+
+	parent = mdev_get_parent(type->parent);
+	if (!parent)
+		return -EINVAL;
+
+	mutex_lock(&parent->lock);
+
+	/* Check for duplicate */
+	if (mdev_device_exist(parent, uuid)) {
+		ret = -EEXIST;
+		goto create_err;
+	}
+
+	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+	if (!mdev) {
+		ret = -ENOMEM;
+		goto create_err;
+	}
+
+	memcpy(&mdev->uuid, &uuid, sizeof(uuid_le));
+	mdev->parent = parent;
+	kref_init(&mdev->ref);
+
+	mdev->dev.parent  = dev;
+	mdev->dev.bus     = &mdev_bus_type;
+	mdev->dev.release = mdev_device_release;
+	dev_set_name(&mdev->dev, "%pUl", uuid.b);
+
+	ret = device_register(&mdev->dev);
+	if (ret) {
+		put_device(&mdev->dev);
+		goto create_err;
+	}
+
+	ret = mdev_device_create_ops(kobj, mdev);
+	if (ret)
+		goto create_failed;
+
+	ret = mdev_create_sysfs_files(&mdev->dev, type);
+	if (ret) {
+		mdev_device_remove_ops(mdev, true);
+		goto create_failed;
+	}
+
+	mdev->type_kobj = kobj;
+	dev_dbg(&mdev->dev, "MDEV: created\n");
+
+	mutex_unlock(&parent->lock);
+	return ret;
+
+create_failed:
+	device_unregister(&mdev->dev);
+
+create_err:
+	mutex_unlock(&parent->lock);
+	mdev_put_parent(parent);
+	return ret;
+}
+
+int mdev_device_remove(struct device *dev, bool force_remove)
+{
+	struct mdev_device *mdev;
+	struct parent_device *parent;
+	struct mdev_type *type;
+	int ret;
+
+	mdev = to_mdev_device(dev);
+	type = to_mdev_type(mdev->type_kobj);
+	parent = mdev->parent;
+	mutex_lock(&parent->lock);
+
+	ret = mdev_device_remove_ops(mdev, force_remove);
+	if (ret) {
+		mutex_unlock(&parent->lock);
+		return ret;
+	}
+
+	mdev_remove_sysfs_files(dev, type);
+	device_unregister(dev);
+	mutex_unlock(&parent->lock);
+	mdev_put_parent(parent);
+	return ret;
+}
+
+static int __init mdev_init(void)
+{
+	return mdev_bus_register();
+}
+
+static void __exit mdev_exit(void)
+{
+	if (mdev_bus_compat_class)
+		class_compat_unregister(mdev_bus_compat_class);
+
+	mdev_bus_unregister();
+}
+
+module_init(mdev_init)
+module_exit(mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
new file mode 100644
index 000000000000..6c19a2f6b5a2
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -0,0 +1,120 @@
+/*
+ * MDEV driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/iommu.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+static int mdev_attach_iommu(struct mdev_device *mdev)
+{
+	int ret;
+	struct iommu_group *group;
+
+	group = iommu_group_alloc();
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = iommu_group_add_device(group, &mdev->dev);
+	if (ret)
+		goto attach_fail;
+
+	dev_info(&mdev->dev, "MDEV: group_id = %d\n", iommu_group_id(group));
+attach_fail:
+	iommu_group_put(group);
+	return ret;
+}
+
+static void mdev_detach_iommu(struct mdev_device *mdev)
+{
+	iommu_group_remove_device(&mdev->dev);
+	dev_info(&mdev->dev, "MDEV: detaching iommu\n");
+}
+
+static int mdev_probe(struct device *dev)
+{
+	struct mdev_driver *drv = to_mdev_driver(dev->driver);
+	struct mdev_device *mdev = to_mdev_device(dev);
+	int ret;
+
+	ret = mdev_attach_iommu(mdev);
+	if (ret)
+		return ret;
+
+	if (drv && drv->probe) {
+		ret = drv->probe(dev);
+		if (ret)
+			mdev_detach_iommu(mdev);
+	}
+
+	return ret;
+}
+
+static int mdev_remove(struct device *dev)
+{
+	struct mdev_driver *drv = to_mdev_driver(dev->driver);
+	struct mdev_device *mdev = to_mdev_device(dev);
+
+	if (drv && drv->remove)
+		drv->remove(dev);
+
+	mdev_detach_iommu(mdev);
+
+	return 0;
+}
+
+struct bus_type mdev_bus_type = {
+	.name		= "mdev",
+	.probe		= mdev_probe,
+	.remove		= mdev_remove,
+};
+EXPORT_SYMBOL_GPL(mdev_bus_type);
+
+/**
+ * mdev_register_driver - register a new MDEV driver
+ * @drv: the driver to register
+ * @owner: module owner of driver to be registered
+ *
+ * Returns a negative value on error, otherwise 0.
+ **/
+int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
+{
+	/* initialize common driver fields */
+	drv->driver.name = drv->name;
+	drv->driver.bus = &mdev_bus_type;
+	drv->driver.owner = owner;
+
+	/* register with core */
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_register_driver);
+
+/*
+ * mdev_unregister_driver - unregister MDEV driver
+ * @drv: the driver to unregister
+ */
+void mdev_unregister_driver(struct mdev_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_unregister_driver);
+
+int mdev_bus_register(void)
+{
+	return bus_register(&mdev_bus_type);
+}
+
+void mdev_bus_unregister(void)
+{
+	bus_unregister(&mdev_bus_type);
+}
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
new file mode 100644
index 000000000000..d35097cbf3d7
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -0,0 +1,41 @@
+/*
+ * Mediated device interal definitions
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#ifndef MDEV_PRIVATE_H
+#define MDEV_PRIVATE_H
+
+int  mdev_bus_register(void);
+void mdev_bus_unregister(void);
+
+struct mdev_type {
+	struct kobject kobj;
+	struct kobject *devices_kobj;
+	struct parent_device *parent;
+	struct list_head next;
+	struct attribute_group *group;
+};
+
+#define to_mdev_type_attr(_attr)	\
+	container_of(_attr, struct mdev_type_attribute, attr)
+#define to_mdev_type(_kobj)		\
+	container_of(_kobj, struct mdev_type, kobj)
+
+int  parent_create_sysfs_files(struct parent_device *parent);
+void parent_remove_sysfs_files(struct parent_device *parent);
+
+int  mdev_create_sysfs_files(struct device *dev, struct mdev_type *type);
+void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type);
+
+int  mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid);
+int  mdev_device_remove(struct device *dev, bool force_remove);
+
+#endif /* MDEV_PRIVATE_H */
diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
new file mode 100644
index 000000000000..04f9b2925e6d
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -0,0 +1,286 @@
+/*
+ * File attributes for Mediated devices
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/sysfs.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uuid.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+/* Static functions */
+
+static ssize_t mdev_type_attr_show(struct kobject *kobj,
+				     struct attribute *__attr, char *buf)
+{
+	struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
+	struct mdev_type *type = to_mdev_type(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->show)
+		ret = attr->show(kobj, type->parent->dev, buf);
+	return ret;
+}
+
+static ssize_t mdev_type_attr_store(struct kobject *kobj,
+				      struct attribute *__attr,
+				      const char *buf, size_t count)
+{
+	struct mdev_type_attribute *attr = to_mdev_type_attr(__attr);
+	struct mdev_type *type = to_mdev_type(kobj);
+	ssize_t ret = -EIO;
+
+	if (attr->store)
+		ret = attr->store(&type->kobj, type->parent->dev, buf, count);
+	return ret;
+}
+
+static const struct sysfs_ops mdev_type_sysfs_ops = {
+	.show = mdev_type_attr_show,
+	.store = mdev_type_attr_store,
+};
+
+static ssize_t create_store(struct kobject *kobj, struct device *dev,
+			    const char *buf, size_t count)
+{
+	char *str;
+	uuid_le uuid;
+	int ret;
+
+	if ((count < UUID_STRING_LEN) || (count > UUID_STRING_LEN + 1))
+		return -EINVAL;
+
+	str = kstrndup(buf, count, GFP_KERNEL);
+	if (!str)
+		return -ENOMEM;
+
+	ret = uuid_le_to_bin(str, &uuid);
+	kfree(str);
+	if (ret)
+		return ret;
+
+	ret = mdev_device_create(kobj, dev, uuid);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+MDEV_TYPE_ATTR_WO(create);
+
+static void mdev_type_release(struct kobject *kobj)
+{
+	struct mdev_type *type = to_mdev_type(kobj);
+
+	pr_debug("Releasing group %s\n", kobj->name);
+	kfree(type);
+}
+
+static struct kobj_type mdev_type_ktype = {
+	.sysfs_ops = &mdev_type_sysfs_ops,
+	.release = mdev_type_release,
+};
+
+struct mdev_type *add_mdev_supported_type(struct parent_device *parent,
+					  struct attribute_group *group)
+{
+	struct mdev_type *type;
+	int ret;
+
+	if (!group->name) {
+		pr_err("%s: Type name empty!\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	type = kzalloc(sizeof(*type), GFP_KERNEL);
+	if (!type)
+		return ERR_PTR(-ENOMEM);
+
+	type->kobj.kset = parent->mdev_types_kset;
+
+	ret = kobject_init_and_add(&type->kobj, &mdev_type_ktype, NULL,
+				   "%s-%s", dev_driver_string(parent->dev),
+				   group->name);
+	if (ret) {
+		kfree(type);
+		return ERR_PTR(ret);
+	}
+
+	ret = sysfs_create_file(&type->kobj, &mdev_type_attr_create.attr);
+	if (ret)
+		goto attr_create_failed;
+
+	type->devices_kobj = kobject_create_and_add("devices", &type->kobj);
+	if (!type->devices_kobj) {
+		ret = -ENOMEM;
+		goto attr_devices_failed;
+	}
+
+	ret = sysfs_create_files(&type->kobj,
+				 (const struct attribute **)group->attrs);
+	if (ret) {
+		ret = -ENOMEM;
+		goto attrs_failed;
+	}
+
+	type->group = group;
+	type->parent = parent;
+	return type;
+
+attrs_failed:
+	kobject_put(type->devices_kobj);
+attr_devices_failed:
+	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
+attr_create_failed:
+	kobject_del(&type->kobj);
+	kobject_put(&type->kobj);
+	return ERR_PTR(ret);
+}
+
+static void remove_mdev_supported_type(struct mdev_type *type)
+{
+	sysfs_remove_files(&type->kobj,
+			   (const struct attribute **)type->group->attrs);
+	kobject_put(type->devices_kobj);
+	sysfs_remove_file(&type->kobj, &mdev_type_attr_create.attr);
+	kobject_del(&type->kobj);
+	kobject_put(&type->kobj);
+}
+
+static int add_mdev_supported_type_groups(struct parent_device *parent)
+{
+	int i;
+
+	for (i = 0; parent->ops->supported_type_groups[i]; i++) {
+		struct mdev_type *type;
+
+		type = add_mdev_supported_type(parent,
+					parent->ops->supported_type_groups[i]);
+		if (IS_ERR(type)) {
+			struct mdev_type *ltype, *tmp;
+
+			list_for_each_entry_safe(ltype, tmp, &parent->type_list,
+						  next) {
+				list_del(&ltype->next);
+				remove_mdev_supported_type(ltype);
+			}
+			return PTR_ERR(type);
+		}
+		list_add(&type->next, &parent->type_list);
+	}
+	return 0;
+}
+
+/* mdev sysfs Functions */
+void parent_remove_sysfs_files(struct parent_device *parent)
+{
+	struct mdev_type *type, *tmp;
+
+	list_for_each_entry_safe(type, tmp, &parent->type_list, next) {
+		list_del(&type->next);
+		remove_mdev_supported_type(type);
+	}
+
+	sysfs_remove_groups(&parent->dev->kobj, parent->ops->dev_attr_groups);
+	kset_unregister(parent->mdev_types_kset);
+}
+
+int parent_create_sysfs_files(struct parent_device *parent)
+{
+	int ret;
+
+	parent->mdev_types_kset = kset_create_and_add("mdev_supported_types",
+					       NULL, &parent->dev->kobj);
+
+	if (!parent->mdev_types_kset)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&parent->type_list);
+
+	ret = sysfs_create_groups(&parent->dev->kobj,
+				  parent->ops->dev_attr_groups);
+	if (ret)
+		goto create_err;
+
+	ret = add_mdev_supported_type_groups(parent);
+	if (ret)
+		sysfs_remove_groups(&parent->dev->kobj,
+				    parent->ops->dev_attr_groups);
+	else
+		return ret;
+
+create_err:
+	kset_unregister(parent->mdev_types_kset);
+	return ret;
+}
+
+static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val && device_remove_file_self(dev, attr)) {
+		int ret;
+
+		ret = mdev_device_remove(dev, false);
+		if (ret) {
+			device_create_file(dev, attr);
+			return ret;
+		}
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(remove);
+
+static const struct attribute *mdev_device_attrs[] = {
+	&dev_attr_remove.attr,
+	NULL,
+};
+
+int  mdev_create_sysfs_files(struct device *dev, struct mdev_type *type)
+{
+	int ret;
+
+	ret = sysfs_create_files(&dev->kobj, mdev_device_attrs);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_link(type->devices_kobj, &dev->kobj, dev_name(dev));
+	if (ret)
+		goto device_link_failed;
+
+	ret = sysfs_create_link(&dev->kobj, &type->kobj, "mdev_type");
+	if (ret)
+		goto type_link_failed;
+
+	return ret;
+
+type_link_failed:
+	sysfs_remove_link(type->devices_kobj, dev_name(dev));
+device_link_failed:
+	sysfs_remove_files(&dev->kobj, mdev_device_attrs);
+	return ret;
+}
+
+void mdev_remove_sysfs_files(struct device *dev, struct mdev_type *type)
+{
+	sysfs_remove_link(&dev->kobj, "mdev_type");
+	sysfs_remove_link(type->devices_kobj, dev_name(dev));
+	sysfs_remove_files(&dev->kobj, mdev_device_attrs);
+}
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
new file mode 100644
index 000000000000..4900cc472364
--- /dev/null
+++ b/include/linux/mdev.h
@@ -0,0 +1,168 @@
+/*
+ * Mediated device definition
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#ifndef MDEV_H
+#define MDEV_H
+
+/* Parent Device */
+struct parent_device {
+	struct device		*dev;
+	const struct parent_ops	*ops;
+
+	/* internal */
+	struct kref		ref;
+	struct mutex		lock;
+	struct list_head	next;
+	struct kset		*mdev_types_kset;
+	struct list_head	type_list;
+};
+
+/* Mediated device */
+struct mdev_device {
+	struct device		dev;
+	struct parent_device	*parent;
+	uuid_le			uuid;
+	void			*driver_data;
+
+	/* internal */
+	struct kref		ref;
+	struct list_head	next;
+	struct kobject		*type_kobj;
+};
+
+/**
+ * struct parent_ops - Structure to be registered for each parent device to
+ * register the device to mdev module.
+ *
+ * @owner:		The module owner.
+ * @dev_attr_groups:	Attributes of the parent device.
+ * @mdev_attr_groups:	Attributes of the mediated device.
+ * @supported_type_groups: Attributes to define supported types. It is mandatory
+ *			to provide supported types.
+ * @create:		Called to allocate basic resources in parent device's
+ *			driver for a particular mediated device. It is
+ *			mandatory to provide create ops.
+ *			@kobj: kobject of type for which 'create' is called.
+ *			@mdev: mdev_device structure on of mediated device
+ *			      that is being created
+ *			Returns integer: success (0) or error (< 0)
+ * @remove:		Called to free resources in parent device's driver for a
+ *			a mediated device. It is mandatory to provide 'remove'
+ *			ops.
+ *			@mdev: mdev_device device structure which is being
+ *			       destroyed
+ *			Returns integer: success (0) or error (< 0)
+ * @open:		Open mediated device.
+ *			@mdev: mediated device.
+ *			Returns integer: success (0) or error (< 0)
+ * @release:		release mediated device
+ *			@mdev: mediated device.
+ * @read:		Read emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: read buffer
+ *			@count: number of bytes to read
+ *			@ppos: address.
+ *			Retuns number on bytes read on success or error.
+ * @write:		Write emulation callback
+ *			@mdev: mediated device structure
+ *			@buf: write buffer
+ *			@count: number of bytes to be written
+ *			@ppos: address.
+ *			Retuns number on bytes written on success or error.
+ * @ioctl:		IOCTL callback
+ *			@mdev: mediated device structure
+ *			@cmd: ioctl command
+ *			@arg: arguments to ioctl
+ * @mmap:		mmap callback
+ *			@mdev: mediated device structure
+ *			@vma: vma structure
+ * Parent device that support mediated device should be registered with mdev
+ * module with parent_ops structure.
+ **/
+
+struct parent_ops {
+	struct module   *owner;
+	const struct attribute_group **dev_attr_groups;
+	const struct attribute_group **mdev_attr_groups;
+	struct attribute_group **supported_type_groups;
+
+	int     (*create)(struct kobject *kobj, struct mdev_device *mdev);
+	int     (*remove)(struct mdev_device *mdev);
+	int     (*open)(struct mdev_device *mdev);
+	void    (*release)(struct mdev_device *mdev);
+	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
+			size_t count, loff_t *ppos);
+	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
+			 size_t count, loff_t *ppos);
+	ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
+			 unsigned long arg);
+	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+};
+
+/* interface for exporting mdev supported type attributes */
+struct mdev_type_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
+	ssize_t (*store)(struct kobject *kobj, struct device *dev,
+			 const char *buf, size_t count);
+};
+
+#define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\
+struct mdev_type_attribute mdev_type_attr_##_name =		\
+	__ATTR(_name, _mode, _show, _store)
+#define MDEV_TYPE_ATTR_RW(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
+#define MDEV_TYPE_ATTR_RO(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
+#define MDEV_TYPE_ATTR_WO(_name) \
+	struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
+
+/**
+ * struct mdev_driver - Mediated device driver
+ * @name: driver name
+ * @probe: called when new device created
+ * @remove: called when device removed
+ * @driver: device driver structure
+ *
+ **/
+struct mdev_driver {
+	const char *name;
+	int  (*probe)(struct device *dev);
+	void (*remove)(struct device *dev);
+	struct device_driver driver;
+};
+
+#define to_mdev_driver(drv)	container_of(drv, struct mdev_driver, driver)
+#define to_mdev_device(dev)	container_of(dev, struct mdev_device, dev)
+
+static inline void *mdev_get_drvdata(struct mdev_device *mdev)
+{
+	return mdev->driver_data;
+}
+
+static inline void mdev_set_drvdata(struct mdev_device *mdev, void *data)
+{
+	mdev->driver_data = data;
+}
+
+extern struct bus_type mdev_bus_type;
+
+#define dev_is_mdev(d) ((d)->bus == &mdev_bus_type)
+
+extern int  mdev_register_device(struct device *dev,
+				 const struct parent_ops *ops);
+extern void mdev_unregister_device(struct device *dev);
+
+extern int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
+extern void mdev_unregister_driver(struct mdev_driver *drv);
+
+#endif /* MDEV_H */
-- 
2.7.0

^ permalink raw reply related

* [Qemu-devel] [PATCH v12 03/22] vfio: Rearrange functions to get vfio_group from dev
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

This patch rearranges functions to get vfio_group from device

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>

Change-Id: I1f93262bdbab75094bc24b087b29da35ba70c4c6
---
 drivers/vfio/vfio.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index d1d70e0b011b..23bc86c1d05d 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -480,6 +480,21 @@ static struct vfio_group *vfio_group_get_from_minor(int minor)
 	return group;
 }
 
+static struct vfio_group *vfio_group_get_from_dev(struct device *dev)
+{
+	struct iommu_group *iommu_group;
+	struct vfio_group *group;
+
+	iommu_group = iommu_group_get(dev);
+	if (!iommu_group)
+		return NULL;
+
+	group = vfio_group_get_from_iommu(iommu_group);
+	iommu_group_put(iommu_group);
+
+	return group;
+}
+
 /**
  * Device objects - create, release, get, put, search
  */
@@ -811,16 +826,10 @@ EXPORT_SYMBOL_GPL(vfio_add_group_dev);
  */
 struct vfio_device *vfio_device_get_from_dev(struct device *dev)
 {
-	struct iommu_group *iommu_group;
 	struct vfio_group *group;
 	struct vfio_device *device;
 
-	iommu_group = iommu_group_get(dev);
-	if (!iommu_group)
-		return NULL;
-
-	group = vfio_group_get_from_iommu(iommu_group);
-	iommu_group_put(iommu_group);
+	group = vfio_group_get_from_dev(dev);
 	if (!group)
 		return NULL;
 
-- 
2.7.0

^ permalink raw reply related

* [Qemu-devel] [PATCH v12 02/22] vfio: VFIO based driver for Mediated devices
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

vfio_mdev driver registers with mdev core driver.
mdev core driver creates mediated device and calls probe routine of
vfio_mdev driver for each device.
Probe routine of vfio_mdev driver adds mediated device to VFIO core module

This driver forms a shim layer that pass through VFIO devices operations
to vendor driver for mediated devices.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>

Change-Id: I583f4734752971d3d112324d69e2508c88f359ec
---
 drivers/vfio/mdev/Kconfig     |   7 ++
 drivers/vfio/mdev/Makefile    |   1 +
 drivers/vfio/mdev/mdev_core.c |  16 ++++-
 drivers/vfio/mdev/vfio_mdev.c | 148 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 171 insertions(+), 1 deletion(-)
 create mode 100644 drivers/vfio/mdev/vfio_mdev.c

diff --git a/drivers/vfio/mdev/Kconfig b/drivers/vfio/mdev/Kconfig
index 258481d65ebd..1aa0391d74f2 100644
--- a/drivers/vfio/mdev/Kconfig
+++ b/drivers/vfio/mdev/Kconfig
@@ -7,3 +7,10 @@ config VFIO_MDEV
 	  Provides a framework to virtualize devices.
 
 	  If you don't know what do here, say N.
+
+config VFIO_MDEV_DEVICE
+	tristate "VFIO support for Mediated devices"
+	depends on VFIO && VFIO_MDEV
+	default n
+	help
+	  VFIO based driver for mediated devices.
diff --git a/drivers/vfio/mdev/Makefile b/drivers/vfio/mdev/Makefile
index 31bc04801d94..fa2d5ea466ee 100644
--- a/drivers/vfio/mdev/Makefile
+++ b/drivers/vfio/mdev/Makefile
@@ -2,3 +2,4 @@
 mdev-y := mdev_core.o mdev_sysfs.o mdev_driver.o
 
 obj-$(CONFIG_VFIO_MDEV) += mdev.o
+obj-$(CONFIG_VFIO_MDEV_DEVICE) += vfio_mdev.o
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 613e8a8a3b2a..1e0714ebc56a 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -354,7 +354,21 @@ int mdev_device_remove(struct device *dev, bool force_remove)
 
 static int __init mdev_init(void)
 {
-	return mdev_bus_register();
+	int ret;
+
+	ret = mdev_bus_register();
+	if (ret) {
+		pr_err("Failed to register mdev bus\n");
+		return ret;
+	}
+
+	/*
+	 * Attempt to load known vfio_mdev.  This gives us a working environment
+	 * without the user needing to explicitly load vfio_mdev driver.
+	 */
+	request_module_nowait("vfio_mdev");
+
+	return ret;
 }
 
 static void __exit mdev_exit(void)
diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
new file mode 100644
index 000000000000..ffc36758cb84
--- /dev/null
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -0,0 +1,148 @@
+/*
+ * VFIO based driver for Mediated device
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ *     Author: Neo Jia <cjia@nvidia.com>
+ *             Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * 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.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vfio.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+#define DRIVER_VERSION  "0.1"
+#define DRIVER_AUTHOR   "NVIDIA Corporation"
+#define DRIVER_DESC     "VFIO based driver for Mediated device"
+
+static int vfio_mdev_open(void *device_data)
+{
+	struct mdev_device *mdev = device_data;
+	struct parent_device *parent = mdev->parent;
+	int ret;
+
+	if (unlikely(!parent->ops->open))
+		return -EINVAL;
+
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	ret = parent->ops->open(mdev);
+	if (ret)
+		module_put(THIS_MODULE);
+
+	return ret;
+}
+
+static void vfio_mdev_release(void *device_data)
+{
+	struct mdev_device *mdev = device_data;
+	struct parent_device *parent = mdev->parent;
+
+	if (likely(parent->ops->release))
+		parent->ops->release(mdev);
+
+	module_put(THIS_MODULE);
+}
+
+static long vfio_mdev_unlocked_ioctl(void *device_data,
+				     unsigned int cmd, unsigned long arg)
+{
+	struct mdev_device *mdev = device_data;
+	struct parent_device *parent = mdev->parent;
+
+	if (unlikely(!parent->ops->ioctl))
+		return -EINVAL;
+
+	return parent->ops->ioctl(mdev, cmd, arg);
+}
+
+static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
+			      size_t count, loff_t *ppos)
+{
+	struct mdev_device *mdev = device_data;
+	struct parent_device *parent = mdev->parent;
+
+	if (unlikely(!parent->ops->read))
+		return -EINVAL;
+
+	return parent->ops->read(mdev, buf, count, ppos);
+}
+
+static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	struct mdev_device *mdev = device_data;
+	struct parent_device *parent = mdev->parent;
+
+	if (unlikely(!parent->ops->write))
+		return -EINVAL;
+
+	return parent->ops->write(mdev, buf, count, ppos);
+}
+
+static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)
+{
+	struct mdev_device *mdev = device_data;
+	struct parent_device *parent = mdev->parent;
+
+	if (unlikely(!parent->ops->mmap))
+		return -EINVAL;
+
+	return parent->ops->mmap(mdev, vma);
+}
+
+static const struct vfio_device_ops vfio_mdev_dev_ops = {
+	.name		= "vfio-mdev",
+	.open		= vfio_mdev_open,
+	.release	= vfio_mdev_release,
+	.ioctl		= vfio_mdev_unlocked_ioctl,
+	.read		= vfio_mdev_read,
+	.write		= vfio_mdev_write,
+	.mmap		= vfio_mdev_mmap,
+};
+
+int vfio_mdev_probe(struct device *dev)
+{
+	struct mdev_device *mdev = to_mdev_device(dev);
+
+	return vfio_add_group_dev(dev, &vfio_mdev_dev_ops, mdev);
+}
+
+void vfio_mdev_remove(struct device *dev)
+{
+	vfio_del_group_dev(dev);
+}
+
+struct mdev_driver vfio_mdev_driver = {
+	.name	= "vfio_mdev",
+	.probe	= vfio_mdev_probe,
+	.remove	= vfio_mdev_remove,
+};
+
+static int __init vfio_mdev_init(void)
+{
+	return mdev_register_driver(&vfio_mdev_driver, THIS_MODULE);
+}
+
+static void __exit vfio_mdev_exit(void)
+{
+	mdev_unregister_driver(&vfio_mdev_driver);
+}
+
+module_init(vfio_mdev_init)
+module_exit(vfio_mdev_exit)
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
-- 
2.7.0

^ permalink raw reply related

* [Qemu-devel] [PATCH v12 04/22] vfio: Common function to increment container_users
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

This change rearrange functions to have common function to increment
container_users

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Jike Song <jike.song@intel.com>

Change-Id: I8bdeb352bc8439b107ffd519480fd4dc238677f2
---
 drivers/vfio/vfio.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 23bc86c1d05d..2e83bdf007fe 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1385,6 +1385,23 @@ static bool vfio_group_viable(struct vfio_group *group)
 					 group, vfio_dev_viable) == 0);
 }
 
+static int vfio_group_add_container_user(struct vfio_group *group)
+{
+	if (!atomic_inc_not_zero(&group->container_users))
+		return -EINVAL;
+
+	if (group->noiommu) {
+		atomic_dec(&group->container_users);
+		return -EPERM;
+	}
+	if (!group->container->iommu_driver || !vfio_group_viable(group)) {
+		atomic_dec(&group->container_users);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static const struct file_operations vfio_device_fops;
 
 static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
@@ -1694,23 +1711,14 @@ static const struct file_operations vfio_device_fops = {
 struct vfio_group *vfio_group_get_external_user(struct file *filep)
 {
 	struct vfio_group *group = filep->private_data;
+	int ret;
 
 	if (filep->f_op != &vfio_group_fops)
 		return ERR_PTR(-EINVAL);
 
-	if (!atomic_inc_not_zero(&group->container_users))
-		return ERR_PTR(-EINVAL);
-
-	if (group->noiommu) {
-		atomic_dec(&group->container_users);
-		return ERR_PTR(-EPERM);
-	}
-
-	if (!group->container->iommu_driver ||
-			!vfio_group_viable(group)) {
-		atomic_dec(&group->container_users);
-		return ERR_PTR(-EINVAL);
-	}
+	ret = vfio_group_add_container_user(group);
+	if (ret)
+		return ERR_PTR(ret);
 
 	vfio_group_get(group);
 
-- 
2.7.0

^ permalink raw reply related

* [Qemu-devel] [PATCH v12 05/22] vfio iommu: Added pin and unpin callback functions to vfio_iommu_driver_ops
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

Added APIs for pining and unpining set of pages. These call back into
backend iommu module to actually pin and unpin pages.
Added two new callback functions to struct vfio_iommu_driver_ops. Backend
IOMMU module that supports pining and unpinning pages for mdev devices
should provide these functions.

Renamed static functions in vfio_type1_iommu.c to resolve conflicts

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: Ia7417723aaae86bec2959ad9ae6c2915ddd340e0
---
 drivers/vfio/vfio.c             | 103 ++++++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio_iommu_type1.c |  20 ++++----
 include/linux/vfio.h            |  12 ++++-
 3 files changed, 124 insertions(+), 11 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 2e83bdf007fe..7dcfbca2016a 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1799,6 +1799,109 @@ void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset)
 }
 EXPORT_SYMBOL_GPL(vfio_info_cap_shift);
 
+
+/*
+ * Pin a set of guest PFNs and return their associated host PFNs for local
+ * domain only.
+ * @dev [in] : device
+ * @user_pfn [in]: array of user/guest PFNs to be unpinned. Number of user/guest
+ *		  PFNs should not be greater than PAGE_SIZE.
+ * @npage [in] :count of elements in array.  This count should not be greater
+ *		than PAGE_SIZE.
+ * @prot [in] : protection flags
+ * @phys_pfn[out] : array of host PFNs
+ * Return error or number of pages pinned.
+ */
+int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int npage,
+		   int prot, unsigned long *phys_pfn)
+{
+	struct vfio_container *container;
+	struct vfio_group *group;
+	struct vfio_iommu_driver *driver;
+	int ret;
+
+	if (!dev || !user_pfn || !phys_pfn || !npage)
+		return -EINVAL;
+
+	if (npage >= PAGE_SIZE)
+		return -E2BIG;
+
+	group = vfio_group_get_from_dev(dev);
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = vfio_group_add_container_user(group);
+	if (ret)
+		goto err_pin_pages;
+
+	container = group->container;
+	down_read(&container->group_lock);
+
+	driver = container->iommu_driver;
+	if (likely(driver && driver->ops->pin_pages))
+		ret = driver->ops->pin_pages(container->iommu_data, user_pfn,
+					     npage, prot, phys_pfn);
+	else
+		ret = -ENOTTY;
+
+	up_read(&container->group_lock);
+	vfio_group_try_dissolve_container(group);
+
+err_pin_pages:
+	vfio_group_put(group);
+	return ret;
+}
+EXPORT_SYMBOL(vfio_pin_pages);
+
+/*
+ * Unpin set of host PFNs for local domain only.
+ * @dev [in] : device
+ * @user_pfn [in]: array of user/guest PFNs to be unpinned. Number of user/guest
+ *		  PFNs should not be greater than PAGE_SIZE.
+ * @npage [in] :count of elements in array.  This count should not be greater
+ *		than PAGE_SIZE.
+ * Return error or number of pages unpinned.
+ */
+int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn, int npage)
+{
+	struct vfio_container *container;
+	struct vfio_group *group;
+	struct vfio_iommu_driver *driver;
+	int ret;
+
+	if (!dev || !user_pfn || !npage)
+		return -EINVAL;
+
+	if (npage >= PAGE_SIZE)
+		return -E2BIG;
+
+	group = vfio_group_get_from_dev(dev);
+	if (IS_ERR(group))
+		return PTR_ERR(group);
+
+	ret = vfio_group_add_container_user(group);
+	if (ret)
+		goto err_unpin_pages;
+
+	container = group->container;
+	down_read(&container->group_lock);
+
+	driver = container->iommu_driver;
+	if (likely(driver && driver->ops->unpin_pages))
+		ret = driver->ops->unpin_pages(container->iommu_data, user_pfn,
+					       npage);
+	else
+		ret = -ENOTTY;
+
+	up_read(&container->group_lock);
+	vfio_group_try_dissolve_container(group);
+
+err_unpin_pages:
+	vfio_group_put(group);
+	return ret;
+}
+EXPORT_SYMBOL(vfio_unpin_pages);
+
 /**
  * Module/class support
  */
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 2ba19424e4a1..9f3d58d3dfaf 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -259,8 +259,8 @@ static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
  * the iommu can only map chunks of consecutive pfns anyway, so get the
  * first page and all consecutive pages with the same locking.
  */
-static long vfio_pin_pages(unsigned long vaddr, long npage,
-			   int prot, unsigned long *pfn_base)
+static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
+				  int prot, unsigned long *pfn_base)
 {
 	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 	bool lock_cap = capable(CAP_IPC_LOCK);
@@ -318,8 +318,8 @@ static long vfio_pin_pages(unsigned long vaddr, long npage,
 	return i;
 }
 
-static long vfio_unpin_pages(unsigned long pfn, long npage,
-			     int prot, bool do_accounting)
+static long vfio_unpin_pages_remote(unsigned long pfn, long npage,
+				    int prot, bool do_accounting)
 {
 	unsigned long unlocked = 0;
 	long i;
@@ -382,9 +382,9 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
 		if (WARN_ON(!unmapped))
 			break;
 
-		unlocked += vfio_unpin_pages(phys >> PAGE_SHIFT,
-					     unmapped >> PAGE_SHIFT,
-					     dma->prot, false);
+		unlocked += vfio_unpin_pages_remote(phys >> PAGE_SHIFT,
+						    unmapped >> PAGE_SHIFT,
+						    dma->prot, false);
 		iova += unmapped;
 
 		cond_resched();
@@ -613,8 +613,8 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 
 	while (size) {
 		/* Pin a contiguous chunk of memory */
-		npage = vfio_pin_pages(vaddr + dma->size,
-				       size >> PAGE_SHIFT, prot, &pfn);
+		npage = vfio_pin_pages_remote(vaddr + dma->size,
+					      size >> PAGE_SHIFT, prot, &pfn);
 		if (npage <= 0) {
 			WARN_ON(!npage);
 			ret = (int)npage;
@@ -624,7 +624,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 		/* Map it! */
 		ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, prot);
 		if (ret) {
-			vfio_unpin_pages(pfn, npage, prot, true);
+			vfio_unpin_pages_remote(pfn, npage, prot, true);
 			break;
 		}
 
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 0ecae0b1cd34..86f507d0f585 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -75,7 +75,11 @@ struct vfio_iommu_driver_ops {
 					struct iommu_group *group);
 	void		(*detach_group)(void *iommu_data,
 					struct iommu_group *group);
-
+	int		(*pin_pages)(void *iommu_data, unsigned long *user_pfn,
+				     int npage, int prot,
+				     unsigned long *phys_pfn);
+	int		(*unpin_pages)(void *iommu_data,
+				       unsigned long *user_pfn, int npage);
 };
 
 extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
@@ -127,6 +131,12 @@ static inline long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
 }
 #endif /* CONFIG_EEH */
 
+extern int vfio_pin_pages(struct device *dev, unsigned long *user_pfn,
+			  int npage, int prot, unsigned long *phys_pfn);
+
+extern int vfio_unpin_pages(struct device *dev, unsigned long *user_pfn,
+			    int npage);
+
 /*
  * IRQfd - generic
  */
-- 
2.7.0

^ permalink raw reply related

* [Qemu-devel] [PATCH v12 06/22] vfio iommu type1: Update arguments of vfio_lock_acct
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

Added task structure as input argument to vfio_lock_acct() function.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: I5d3673cc9d3786bb436b395d5f74537f1a36da80
---
 drivers/vfio/vfio_iommu_type1.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 9f3d58d3dfaf..34d17e51dc97 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -150,17 +150,22 @@ static void vfio_lock_acct_bg(struct work_struct *work)
 	kfree(vwork);
 }
 
-static void vfio_lock_acct(long npage)
+static void vfio_lock_acct(struct task_struct *task, long npage)
 {
 	struct vwork *vwork;
 	struct mm_struct *mm;
 
-	if (!current->mm || !npage)
+	if (!npage)
+		return;
+
+	mm = get_task_mm(task);
+	if (!mm)
 		return; /* process exited or nothing to do */
 
-	if (down_write_trylock(&current->mm->mmap_sem)) {
-		current->mm->locked_vm += npage;
-		up_write(&current->mm->mmap_sem);
+	if (down_write_trylock(&mm->mmap_sem)) {
+		mm->locked_vm += npage;
+		up_write(&mm->mmap_sem);
+		mmput(mm);
 		return;
 	}
 
@@ -170,11 +175,8 @@ static void vfio_lock_acct(long npage)
 	 * wouldn't need this silliness
 	 */
 	vwork = kmalloc(sizeof(struct vwork), GFP_KERNEL);
-	if (!vwork)
-		return;
-	mm = get_task_mm(current);
-	if (!mm) {
-		kfree(vwork);
+	if (!vwork) {
+		mmput(mm);
 		return;
 	}
 	INIT_WORK(&vwork->work, vfio_lock_acct_bg);
@@ -285,7 +287,7 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
 
 	if (unlikely(disable_hugepages)) {
 		if (!rsvd)
-			vfio_lock_acct(1);
+			vfio_lock_acct(current, 1);
 		return 1;
 	}
 
@@ -313,7 +315,7 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
 	}
 
 	if (!rsvd)
-		vfio_lock_acct(i);
+		vfio_lock_acct(current, i);
 
 	return i;
 }
@@ -328,7 +330,7 @@ static long vfio_unpin_pages_remote(unsigned long pfn, long npage,
 		unlocked += put_pfn(pfn++, prot);
 
 	if (do_accounting)
-		vfio_lock_acct(-unlocked);
+		vfio_lock_acct(current, -unlocked);
 
 	return unlocked;
 }
@@ -390,7 +392,7 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
 		cond_resched();
 	}
 
-	vfio_lock_acct(-unlocked);
+	vfio_lock_acct(current, -unlocked);
 }
 
 static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
-- 
2.7.0

^ permalink raw reply related

* [PATCH] arago-core-tisdk-image: Fix DEPLOY_SPL_NAME for k2g
From: Jacob Stiffler @ 2016-11-14 15:39 UTC (permalink / raw)
  To: meta-arago

* The k2g machines require that MLO is available in the SDK's
  prebuilt-images.
* Therefore do not unset DEPLOY_SPL_NAME for all keystone machines,
  but only the one which do not require it (k2hk-evm, k2l-evm, and
  k2e).

Signed-off-by: Jacob Stiffler <j-stiffler@ti.com>
---
 meta-arago-distro/recipes-core/images/arago-core-tisdk-image.bb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/meta-arago-distro/recipes-core/images/arago-core-tisdk-image.bb b/meta-arago-distro/recipes-core/images/arago-core-tisdk-image.bb
index f313494..7dfaac1 100644
--- a/meta-arago-distro/recipes-core/images/arago-core-tisdk-image.bb
+++ b/meta-arago-distro/recipes-core/images/arago-core-tisdk-image.bb
@@ -1,7 +1,9 @@
 require arago-core-tisdk-image.inc
 
 DEPLOY_SPL_NAME_omapl138 = ""
-DEPLOY_SPL_NAME_keystone = ""
+DEPLOY_SPL_NAME_k2hk-evm = ""
+DEPLOY_SPL_NAME_k2l-evm = ""
+DEPLOY_SPL_NAME_k2e = ""
 
 ARAGO_TISDK_IMAGE ?= "arago-core-tisdk-image"
 export IMAGE_BASENAME = "${ARAGO_TISDK_IMAGE}"
-- 
2.7.4



^ permalink raw reply related

* Re: [PATCH v5 3/3] clocksource: Add clockevent support to NPS400 driver
From: Daniel Lezcano @ 2016-11-14 15:41 UTC (permalink / raw)
  To: Noam Camus
  Cc: robh+dt@kernel.org, mark.rutland@arm.com, tglx@linutronix.de,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <DB6PR0501MB25183EEEC116B9E97CC01BCFAABC0@DB6PR0501MB2518.eurprd05.prod.outlook.com>

On Mon, Nov 14, 2016 at 03:17:48PM +0000, Noam Camus wrote:
> > From: Daniel Lezcano [mailto:daniel.lezcano@linaro.org] 
> > Sent: Monday, November 14, 2016 4:35 PM
> 
>  
> >The function nps_clkevent_timer_event_setup() writes into the
> >NPS_REG_TIMER0_CTRL register but there is no critical section there. What
> >prevents another HW thread to write this register at the same time ?
> Correct, during my last email to you I noticed that fact and already started
> fixing it.
> 
> >I do believe we have a framework to access shared registers, otherwise a
> >simple spinlock would be simpler and perhaps faster than disabling the
> >entire hardware scheduling for the system, no ?
> When you are saying "we have a framework" do you mean to some generic
> framework in the kernel? 

Yes, IIRC it is regmap but I'm not sure.

> Anyway to my understanding I cannot guarantee this
> atomics during my routines without preventing HW from changing the HW thread
> this core executes.  As SW I am not aware to such HW scheduling, It is much
> same as with interrupts that we disable them when we reach code that might be
> shared by the interrupt handler.

I think there is something I am missing with this HW scheduling thing. Why are
these hw_schd_save/hw_schd_restore functions needed to be called from the
timer driver ? Regarding the explanation, the HW scheduling can happen everywhere
at any time, not only in the timer code but this one is the only one which need
the hw_schd_save/hw_schd_restore calls, why ?

Why,

spin_lock(&lock);
write_aux_reg(...)
spin_unlock(&lock);

can't work ?

IIUC, there can be more than 16 cpus/threads, so calling hw_schd_save /
hw_schd_restore will disable the HW scheduling for the entire system while one
cpu is processing something with these couple of registers, no ?

> >Regarding the comment I did above, it is possible the critical section is
> >reduced and moved into the shutdown function. Thus, the boolean wouldn't be
> >needed anymore, well that is conditional to the above comment. Discard the
> >comment for the moment, until the hw sched vs spinlock vs
> >NPS_REG_TIMER0_CTRL is sorted out.
> OK, I will discard that in the meantime.
> 
> ...
> >> >> +	.set_state_shutdown		=
> >> >> nps_clkevent_timer_shutdown,
> >> 
> >> >Doesn't set_state_shutdown and set_state_oneshot_stopped need to remove
> >> >the HW thread from the TSI ?
> >> You are correct, I will fix that.
> 
> >And tick_resume. Perhaps, that is the reason why NO_HZ hangs.
> What NO_HZ hang are you referring to in this case?  How calling
> nps_clkevent_rm_thread() explain such hang?  Anyway I agree, and will add
> nps_clkevent_rm_thread() to tick_resume.

Actually I meant NOHZ_FULL.
 
> Appreciating your effort and will gladly provide any more information needed
> about our SoC.  -Noam

-- 

 <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

^ permalink raw reply

* [Qemu-devel] [PATCH v12 07/22] vfio iommu type1: Update argument of vaddr_get_pfn()
From: Kirti Wankhede @ 2016-11-14 15:42 UTC (permalink / raw)
  To: alex.williamson, pbonzini, kraxel, cjia
  Cc: qemu-devel, kvm, kevin.tian, jike.song, bjsdjshi, linux-kernel,
	Kirti Wankhede
In-Reply-To: <1479138156-28905-1-git-send-email-kwankhede@nvidia.com>

Update arguments of vaddr_get_pfn() to take struct mm_struct *mm as input
argument.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: I885fd4cd4a9f66f4ee2c1caf58267464ec239f52
---
 drivers/vfio/vfio_iommu_type1.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 34d17e51dc97..52af5fc01d91 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -230,20 +230,36 @@ static int put_pfn(unsigned long pfn, int prot)
 	return 0;
 }
 
-static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
+static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
+			 int prot, unsigned long *pfn)
 {
 	struct page *page[1];
 	struct vm_area_struct *vma;
-	int ret = -EFAULT;
+	int ret;
+
+	if (mm == current->mm) {
+		ret = get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE),
+					  page);
+	} else {
+		unsigned int flags = 0;
+
+		if (prot & IOMMU_WRITE)
+			flags |= FOLL_WRITE;
+
+		down_read(&mm->mmap_sem);
+		ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page,
+					    NULL);
+		up_read(&mm->mmap_sem);
+	}
 
-	if (get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE), page) == 1) {
+	if (ret == 1) {
 		*pfn = page_to_pfn(page[0]);
 		return 0;
 	}
 
-	down_read(&current->mm->mmap_sem);
+	down_read(&mm->mmap_sem);
 
-	vma = find_vma_intersection(current->mm, vaddr, vaddr + 1);
+	vma = find_vma_intersection(mm, vaddr, vaddr + 1);
 
 	if (vma && vma->vm_flags & VM_PFNMAP) {
 		*pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
@@ -251,7 +267,7 @@ static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
 			ret = 0;
 	}
 
-	up_read(&current->mm->mmap_sem);
+	up_read(&mm->mmap_sem);
 
 	return ret;
 }
@@ -272,7 +288,7 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
 	if (!current->mm)
 		return -ENODEV;
 
-	ret = vaddr_get_pfn(vaddr, prot, pfn_base);
+	ret = vaddr_get_pfn(current->mm, vaddr, prot, pfn_base);
 	if (ret)
 		return ret;
 
@@ -295,7 +311,7 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
 	for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
 		unsigned long pfn = 0;
 
-		ret = vaddr_get_pfn(vaddr, prot, &pfn);
+		ret = vaddr_get_pfn(current->mm, vaddr, prot, &pfn);
 		if (ret)
 			break;
 
-- 
2.7.0

^ permalink raw reply related


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