Re: [PATCH 5/6] xen/pvh: balloon and grant changes.

[Stefano Stabellini]

On Sat, 20 Oct 2012, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> 
> For balloon changes we skip setting of local P2M as it's updated
> in Xen. For grant, the shared grant frame is the pfn and not mfn,
> hence its mapped via the same code path as HVM.
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
>  drivers/xen/balloon.c     |   15 +++++++++------
>  drivers/xen/gntdev.c      |    3 ++-
>  drivers/xen/grant-table.c |   26 ++++++++++++++++++++++----
>  3 files changed, 33 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 31ab82f..c825b63 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -361,7 +361,9 @@ static enum bp_state increase_reservation(unsigned long nr_pages)
>  		set_phys_to_machine(pfn, frame_list[i]);
>  
>  		/* Link back into the page tables if not highmem. */
> -		if (xen_pv_domain() && !PageHighMem(page)) {
> +		if (xen_pv_domain() && !PageHighMem(page) &&
> +		    !xen_feature(XENFEAT_auto_translated_physmap)) {
> +
>  			int ret;
>  			ret = HYPERVISOR_update_va_mapping(
>  				(unsigned long)__va(pfn << PAGE_SHIFT),
> @@ -418,12 +420,13 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
>  		scrub_page(page);
>  
>  		if (xen_pv_domain() && !PageHighMem(page)) {
> -			ret = HYPERVISOR_update_va_mapping(
> -				(unsigned long)__va(pfn << PAGE_SHIFT),
> -				__pte_ma(0), 0);
> -			BUG_ON(ret);
> +			if (!xen_feature(XENFEAT_auto_translated_physmap)) {
> +				ret = HYPERVISOR_update_va_mapping(
> +					(unsigned long)__va(pfn << PAGE_SHIFT),
> +					__pte_ma(0), 0);
> +				BUG_ON(ret);
> +			}
>  		}

this change, unlike the one before, actually makes things different for
traditional pv domains in case PageHighMem(page).

The rest looks good.

>  	}
>  
>  	/* Ensure that ballooned highmem pages don't have kmaps. */
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index 610bfc6..d39d54e 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -803,7 +803,8 @@ static int __init gntdev_init(void)
>  	if (!xen_domain())
>  		return -ENODEV;
>  
> -	use_ptemod = xen_pv_domain();
> +	use_ptemod = xen_pv_domain() &&
> +		     !xen_feature(XENFEAT_auto_translated_physmap);
>  
>  	err = misc_register(&gntdev_miscdev);
>  	if (err != 0) {
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index b2b0a37..9c0019d 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -1029,14 +1029,19 @@ 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_feature(XENFEAT_auto_translated_physmap)) {
>  		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.
> @@ -1045,7 +1050,7 @@ 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
> @@ -1108,7 +1113,7 @@ static void gnttab_request_version(void)
>  	int rc;
>  	struct gnttab_set_version gsv;
>  
> -	if (xen_hvm_domain())
> +	if (xen_hvm_domain() || xen_feature(XENFEAT_auto_translated_physmap))
>  		gsv.version = 1;
>  	else
>  		gsv.version = 2;
> @@ -1136,12 +1141,25 @@ 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;
>  
> +	/* PVH note: xen will free existing kmalloc'd mfn in
> +	 * XENMEM_add_to_physmap. TBD/FIXME: use xen ballooning instead of
> +	 * kmalloc(). */
> +	if (xen_pv_domain() && xen_feature(XENFEAT_auto_translated_physmap) &&
> +	    !gnttab_shared.addr) {
> +		gnttab_shared.addr =
> +			kmalloc(max_nr_gframes * PAGE_SIZE, GFP_KERNEL);
> +		if (!gnttab_shared.addr) {
> +			pr_warn("%s", kmsg);
> +			return -ENOMEM;
> +		}
> +	}
>  	if (xen_pv_domain())
>  		return gnttab_map(0, nr_grant_frames - 1);
>  
> -- 
> 1.7.7.6
> 
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