[RFC PATCH 7/8]: PVH: grant changes

[RFC PATCH 7/8]: PVH: grant changes

[Mukesh Rathor]

---
 drivers/xen/gntdev.c      |    2 +-
 drivers/xen/grant-table.c |   26 +++++++++++++++++++++-----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 1ffd03b..ad2d28e 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -802,7 +802,7 @@ static int __init gntdev_init(void)
 	if (!xen_domain())
 		return -ENODEV;
 
-	use_ptemod = xen_pv_domain();
+	use_ptemod = xen_pv_domain() && !xen_pvh_domain();
 
 	err = misc_register(&gntdev_miscdev);
 	if (err != 0) {
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 0bfc1ef..2430133 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -974,14 +974,19 @@ static void gnttab_unmap_frames_v2(void)
 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 {
 	struct gnttab_setup_table setup;
-	unsigned long *frames;
+	unsigned long *frames, start_gpfn;
 	unsigned int nr_gframes = end_idx + 1;
 	int rc;
 
-	if (xen_hvm_domain()) {
+	if (xen_hvm_domain() || xen_pvh_domain()) {
 		struct xen_add_to_physmap xatp;
 		unsigned int i = end_idx;
 		rc = 0;
+
+		if (xen_hvm_domain())
+			start_gpfn = xen_hvm_resume_frames >> PAGE_SHIFT;
+		else
+			start_gpfn = virt_to_pfn(gnttab_shared.addr);
 		/*
 		 * Loop backwards, so that the first hypercall has the largest
 		 * index, ensuring that the table will grow only once.
@@ -990,7 +995,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 			xatp.domid = DOMID_SELF;
 			xatp.idx = i;
 			xatp.space = XENMAPSPACE_grant_table;
-			xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
+			xatp.gpfn = start_gpfn + i;
 			rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
 			if (rc != 0) {
 				printk(KERN_WARNING
@@ -1053,7 +1058,7 @@ static void gnttab_request_version(void)
 	int rc;
 	struct gnttab_set_version gsv;
 
-	if (xen_hvm_domain())
+	if (xen_hvm_domain() || xen_pvh_domain())
 		gsv.version = 1;
 	else
 		gsv.version = 2;
@@ -1081,13 +1086,24 @@ static void gnttab_request_version(void)
 int gnttab_resume(void)
 {
 	unsigned int max_nr_gframes;
+	char *kmsg="Failed to kmalloc pages for pv in hvm grant frames\n";
 
 	gnttab_request_version();
 	max_nr_gframes = gnttab_max_grant_frames();
 	if (max_nr_gframes < nr_grant_frames)
 		return -ENOSYS;
 
-	if (xen_pv_domain())
+	/* PVH note: xen will free existing kmalloc'd mfn in
+	 * XENMEM_add_to_physmap */
+	if (xen_pvh_domain() && !gnttab_shared.addr) {
+		gnttab_shared.addr =
+			kmalloc(max_nr_gframes * PAGE_SIZE, GFP_KERNEL);
+		if ( !gnttab_shared.addr ) {
+			printk(KERN_WARNING "%s", kmsg);
+			return -ENOMEM;
+		}
+	}
+	if (xen_pv_domain() || xen_pvh_domain())
 		return gnttab_map(0, nr_grant_frames - 1);
 
 	if (gnttab_shared.addr == NULL) {
-- 
1.7.2.3

Re: [RFC PATCH 7/8]: PVH: grant changes

[Ian Campbell]

On Thu, 2012-08-16 at 02:06 +0100, Mukesh Rathor wrote:
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index 0bfc1ef..2430133 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -974,14 +974,19 @@ static void gnttab_unmap_frames_v2(void)
>  static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
>  {
>  	struct gnttab_setup_table setup;
> -	unsigned long *frames;
> +	unsigned long *frames, start_gpfn;
>  	unsigned int nr_gframes = end_idx + 1;
>  	int rc;
>  
> -	if (xen_hvm_domain()) {
> +	if (xen_hvm_domain() || xen_pvh_domain()) {
>  		struct xen_add_to_physmap xatp;
>  		unsigned int i = end_idx;
>  		rc = 0;
> +
> +		if (xen_hvm_domain())
> +			start_gpfn = xen_hvm_resume_frames >> PAGE_SHIFT;
> +		else
> +			start_gpfn = virt_to_pfn(gnttab_shared.addr);

I wonder why the HVM case doesn't already use
virt_to_pfn(gnttab_shared.addr) since it appears to set
gnttab_shared.addr:
		gnttab_shared.addr = ioremap(xen_hvm_resume_frames,
						PAGE_SIZE * max_nr_gframes);

Perhaps the result of ioremap isn't amenable to virt_to_pfn (I can never
remember off hand)

>  		/*
>  		 * Loop backwards, so that the first hypercall has the largest
>  		 * index, ensuring that the table will grow only once.
> @@ -990,7 +995,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
>  			xatp.domid = DOMID_SELF;
>  			xatp.idx = i;
>  			xatp.space = XENMAPSPACE_grant_table;
> -			xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
> +			xatp.gpfn = start_gpfn + i;
>  			rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
>  			if (rc != 0) {
>  				printk(KERN_WARNING
> @@ -1053,7 +1058,7 @@ static void gnttab_request_version(void)
>  	int rc;
>  	struct gnttab_set_version gsv;
>  
> -	if (xen_hvm_domain())
> +	if (xen_hvm_domain() || xen_pvh_domain())

Does something stop pvh using v2?

Is it a hypervisor implementation thing? In which case it might be
better for GNTTABOP_set_version to explicitly fail the set attempt? (the
same may well apply to HVM for all I know...)

>  		gsv.version = 1;
>  	else
>  		gsv.version = 2;
> @@ -1081,13 +1086,24 @@ static void gnttab_request_version(void)
>  int gnttab_resume(void)
>  {
>  	unsigned int max_nr_gframes;
> +	char *kmsg="Failed to kmalloc pages for pv in hvm grant frames\n";
>  
>  	gnttab_request_version();
>  	max_nr_gframes = gnttab_max_grant_frames();
>  	if (max_nr_gframes < nr_grant_frames)
>  		return -ENOSYS;
>  
> -	if (xen_pv_domain())
> +	/* PVH note: xen will free existing kmalloc'd mfn in
> +	 * XENMEM_add_to_physmap */
> +	if (xen_pvh_domain() && !gnttab_shared.addr) {
> +		gnttab_shared.addr =
> +			kmalloc(max_nr_gframes * PAGE_SIZE, GFP_KERNEL);
> +		if ( !gnttab_shared.addr ) {
> +			printk(KERN_WARNING "%s", kmsg);

Why this construct instead of just the string literal?

> +			return -ENOMEM;
> +		}
> +	}
> +	if (xen_pv_domain() || xen_pvh_domain())
>  		return gnttab_map(0, nr_grant_frames - 1);
>  
>  	if (gnttab_shared.addr == NULL) {

Re: [RFC PATCH 7/8]: PVH: grant changes

[Mukesh Rathor]

On Fri, 17 Aug 2012 10:52:30 +0100
Ian Campbell <Ian.Campbell@citrix.com> wrote:

> On Thu, 2012-08-16 at 02:06 +0100, Mukesh Rathor wrote:
> > diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> > index 0bfc1ef..2430133 100644
> > --- a/drivers/xen/grant-table.c
> > +++ b/drivers/xen/grant-table.c


> > HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp); if (rc != 0) {
> >  				printk(KERN_WARNING
> > @@ -1053,7 +1058,7 @@ static void gnttab_request_version(void)
> >  	int rc;
> >  	struct gnttab_set_version gsv;
> >  
> > -	if (xen_hvm_domain())
> > +	if (xen_hvm_domain() || xen_pvh_domain())
> 
> Does something stop pvh using v2?

I had some issue related to grstatus field that was added, so punted it
for now. It's phase II which is a big phase now :) :)... 


> >  
> > -	if (xen_pv_domain())
> > +	/* PVH note: xen will free existing kmalloc'd mfn in
> > +	 * XENMEM_add_to_physmap */
> > +	if (xen_pvh_domain() && !gnttab_shared.addr) {
> > +		gnttab_shared.addr =
> > +			kmalloc(max_nr_gframes * PAGE_SIZE,
> > GFP_KERNEL);
> > +		if ( !gnttab_shared.addr ) {
> > +			printk(KERN_WARNING "%s", kmsg);
> 
> Why this construct instead of just the string literal?
 
To keep line overflow. I dont' like code spanning 80 columns. If you split,
then you can't grep.

Re: [RFC PATCH 7/8]: PVH: grant changes

[Ian Campbell]

> > > HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp); if (rc != 0) {
> > >  				printk(KERN_WARNING
> > > @@ -1053,7 +1058,7 @@ static void gnttab_request_version(void)
> > >  	int rc;
> > >  	struct gnttab_set_version gsv;
> > >  
> > > -	if (xen_hvm_domain())
> > > +	if (xen_hvm_domain() || xen_pvh_domain())
> > 
> > Does something stop pvh using v2?
> 
> I had some issue related to grstatus field that was added, so punted it
> for now. It's phase II which is a big phase now :) :)...

It seems like it's got a lot of most independent bits in it, so
hopefully you should get some help ;-)

> > >  
> > > -	if (xen_pv_domain())
> > > +	/* PVH note: xen will free existing kmalloc'd mfn in
> > > +	 * XENMEM_add_to_physmap */
> > > +	if (xen_pvh_domain() && !gnttab_shared.addr) {
> > > +		gnttab_shared.addr =
> > > +			kmalloc(max_nr_gframes * PAGE_SIZE,
> > > GFP_KERNEL);
> > > +		if ( !gnttab_shared.addr ) {
> > > +			printk(KERN_WARNING "%s", kmsg);
> > 
> > Why this construct instead of just the string literal?
>  
> To keep line overflow. I dont' like code spanning 80 columns. If you split,
> then you can't grep.

FWIW CodingStyle relaxes the 80 column limit for literal strings for
exactly this reason.

Ian.