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From: Juergen Gross <jgross@suse.com>
To: Ankur Arora <ankur.a.arora@oracle.com>,
	linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Cc: pbonzini@redhat.com, boris.ostrovsky@oracle.com,
	sstabellini@kernel.org, joao.m.martins@oracle.com,
	konrad.wilk@oracle.com
Subject: Re: [Xen-devel] [RFC PATCH 10/16] xen/balloon: support ballooning in xenhost_t
Date: Mon, 17 Jun 2019 11:28:12 +0200
Message-ID: <c67f2fd9-c837-bc13-492f-f3bed7f01f05@suse.com> (raw)
In-Reply-To: <20190509172540.12398-11-ankur.a.arora@oracle.com>

On 09.05.19 19:25, Ankur Arora wrote:
> Xen ballooning uses hollow struct pages (with the underlying GFNs being
> populated/unpopulated via hypercalls) which are used by the grant logic
> to map grants from other domains.
> 
> This patch allows the default xenhost to provide an alternate ballooning
> allocation mechanism. This is expected to be useful for local xenhosts
> (type xenhost_r0) because unlike Xen, where there is an external
> hypervisor which can change the memory underneath a GFN, that is not
> possible when the hypervisor is running in the same address space
> as the entity doing the ballooning.
> 
> Co-developed-by: Ankur Arora <ankur.a.arora@oracle.com>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
> ---
>   arch/x86/xen/enlighten_hvm.c       |  7 +++++++
>   arch/x86/xen/enlighten_pv.c        |  8 ++++++++
>   drivers/xen/balloon.c              | 19 ++++++++++++++++---
>   drivers/xen/grant-table.c          |  4 ++--
>   drivers/xen/privcmd.c              |  4 ++--
>   drivers/xen/xen-selfballoon.c      |  2 ++
>   drivers/xen/xenbus/xenbus_client.c |  6 +++---
>   drivers/xen/xlate_mmu.c            |  4 ++--
>   include/xen/balloon.h              |  4 ++--
>   include/xen/xenhost.h              | 19 +++++++++++++++++++
>   10 files changed, 63 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 5ef4d6ad920d..08becf574743 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -63,6 +63,7 @@
>   #include <asm/tlb.h>
>   
>   #include <xen/interface/xen.h>
> +#include <xen/xenhost.h>
>   #include <asm/xen/hypervisor.h>
>   #include <asm/xen/hypercall.h>
>   
> @@ -583,12 +584,21 @@ static int add_ballooned_pages(int nr_pages)
>    * @pages: pages returned
>    * @return 0 on success, error otherwise
>    */
> -int alloc_xenballooned_pages(int nr_pages, struct page **pages)
> +int alloc_xenballooned_pages(xenhost_t *xh, int nr_pages, struct page **pages)
>   {
>   	int pgno = 0;
>   	struct page *page;
>   	int ret;
>   
> +	/*
> +	 * xenmem transactions for remote xenhost are disallowed.
> +	 */
> +	if (xh->type == xenhost_r2)
> +		return -EINVAL;

Why don't you set a dummy function returning -EINVAL into the xenhost_r2
structure instead?

> +
> +	if (xh->ops->alloc_ballooned_pages)
> +		return xh->ops->alloc_ballooned_pages(xh, nr_pages, pages);
> +

Please make alloc_xenballooned_pages() an inline wrapper and use the
current implmentaion as the default. This avoids another if ().

>   	mutex_lock(&balloon_mutex);
>   
>   	balloon_stats.target_unpopulated += nr_pages;
> @@ -620,7 +630,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages)
>   	return 0;
>    out_undo:
>   	mutex_unlock(&balloon_mutex);
> -	free_xenballooned_pages(pgno, pages);
> +	free_xenballooned_pages(xh, pgno, pages);
>   	return ret;
>   }
>   EXPORT_SYMBOL(alloc_xenballooned_pages);
> @@ -630,10 +640,13 @@ EXPORT_SYMBOL(alloc_xenballooned_pages);
>    * @nr_pages: Number of pages
>    * @pages: pages to return
>    */
> -void free_xenballooned_pages(int nr_pages, struct page **pages)
> +void free_xenballooned_pages(xenhost_t *xh, int nr_pages, struct page **pages)
>   {
>   	int i;
>   
> +	if (xh->ops->free_ballooned_pages)
> +		return xh->ops->free_ballooned_pages(xh, nr_pages, pages);
> +

Same again: please use an inline wrapper.


Juergen

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  reply index

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-09 17:25 [Xen-devel] [RFC PATCH 00/16] xenhost support Ankur Arora
2019-05-09 17:25 ` [Xen-devel] [RFC PATCH 01/16] x86/xen: add xenhost_t interface Ankur Arora
2019-06-07 15:04   ` Juergen Gross
2019-06-11  7:16     ` Ankur Arora
2019-06-14 11:52       ` Juergen Gross
2019-05-09 17:25 ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 02/16] x86/xen: cpuid support in xenhost_t Ankur Arora
2019-05-09 17:25   ` [Xen-devel] " Ankur Arora
2019-06-12 21:09   ` Andrew Cooper
2019-05-09 17:25 ` [Xen-devel] [RFC PATCH 03/16] x86/xen: make hypercall_page generic Ankur Arora
2019-05-09 17:25 ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 04/16] x86/xen: hypercall support for xenhost_t Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-06-12 21:15   ` Andrew Cooper
2019-06-14  7:20     ` Ankur Arora
2019-06-14  7:35       ` Juergen Gross
2019-06-14  8:00         ` Andrew Cooper
2019-05-09 17:25 ` [RFC PATCH 05/16] x86/xen: add feature support in xenhost_t Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-05-09 17:25 ` [Xen-devel] [RFC PATCH 06/16] x86/xen: add shared_info support to xenhost_t Ankur Arora
2019-06-07 15:08   ` Juergen Gross
2019-06-08  5:01     ` Ankur Arora
2019-05-09 17:25 ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 07/16] x86/xen: make vcpu_info part of xenhost_t Ankur Arora
2019-05-09 17:25   ` [Xen-devel] " Ankur Arora
2019-06-14 11:53   ` Juergen Gross
2019-06-17  6:28     ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 08/16] x86/xen: irq/upcall handling with multiple xenhosts Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-06-14 12:01   ` Juergen Gross
2019-05-09 17:25 ` [RFC PATCH 09/16] xen/evtchn: support evtchn in xenhost_t Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-06-14 12:04   ` Juergen Gross
2019-06-17  6:09     ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 10/16] xen/balloon: support ballooning " Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-06-17  9:28   ` Juergen Gross [this message]
2019-06-19  2:24     ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 11/16] xen/grant-table: make grant-table xenhost aware Ankur Arora
2019-05-09 17:25   ` [Xen-devel] " Ankur Arora
2019-06-17  9:36   ` Juergen Gross
2019-06-19  2:25     ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 12/16] xen/xenbus: support xenbus frontend/backend with xenhost_t Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-06-17  9:50   ` Juergen Gross
2019-06-19  2:38     ` Ankur Arora
2019-05-09 17:25 ` [Xen-devel] [RFC PATCH 13/16] drivers/xen: gnttab, evtchn, xenbus API changes Ankur Arora
2019-06-17 10:07   ` Juergen Gross
2019-06-19  2:55     ` Ankur Arora
2019-05-09 17:25 ` Ankur Arora
2019-05-09 17:25 ` [Xen-devel] [RFC PATCH 14/16] xen/blk: " Ankur Arora
2019-06-17 10:14   ` Juergen Gross
2019-06-19  2:59     ` Ankur Arora
2019-05-09 17:25 ` Ankur Arora
2019-05-09 17:25 ` [RFC PATCH 15/16] xen/net: " Ankur Arora
2019-05-09 17:25 ` [Xen-devel] " Ankur Arora
2019-06-17 10:14   ` Juergen Gross
2019-05-09 17:25 ` [Xen-devel] [RFC PATCH 16/16] xen/grant-table: host_addr fixup in mapping on xenhost_r0 Ankur Arora
2019-06-17 10:55   ` Juergen Gross
2019-06-19  3:02     ` Ankur Arora
2019-05-09 17:25 ` Ankur Arora
2019-06-07 14:51 ` [Xen-devel] [RFC PATCH 00/16] xenhost support Juergen Gross
2019-06-07 15:22   ` Joao Martins
2019-06-07 16:21     ` Juergen Gross
2019-06-08  5:50       ` Ankur Arora
2019-06-08  5:33   ` Ankur Arora

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