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Message-ID: <alpine.DEB.2.02.1312181827280.8667@kaball.uk.xensource.com>
Date: Wed, 18 Dec 2013 18:31:43 +0000
From: Stefano Stabellini <stefano.stabellini@...citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: <xen-devel@...ts.xenproject.org>, <linux-kernel@...r.kernel.org>,
<boris.ostrovsky@...cle.com>, <david.vrabel@...rix.com>,
<mukesh.rathor@...cle.com>, <jbeulich@...e.com>
Subject: Re: [Xen-devel] [PATCH v11 09/12] xen/pvh: Piggyback on PVHVM XenBus
and event channels for PVH.
On Tue, 17 Dec 2013, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@...cle.com>
>
> PVH is a PV guest with a twist - there are certain things
> that work in it like HVM and some like PV. There is
> a similar mode - PVHVM where we run in HVM mode with
> PV code enabled - and this patch explores that.
>
> The most notable PV interfaces are the XenBus and event channels.
> For PVH, we will use XenBus and event channels.
>
> For the XenBus mechanism we piggyback on how it is done for
> PVHVM guests.
>
> Ditto for the event channel mechanism - we piggyback on PVHVM -
> by setting up a specific vector callback and that
> vector ends up calling the event channel mechanism to
> dispatch the events as needed.
>
> This means that from a pvops perspective, we can use
> native_irq_ops instead of the Xen PV specific. Albeit in the
> future we could support pirq_eoi_map. But that is
> a feature request that can be shared with PVHVM.
>
> Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> ---
> arch/x86/xen/enlighten.c | 6 ++++++
> arch/x86/xen/irq.c | 5 ++++-
> drivers/xen/events.c | 5 +++++
> drivers/xen/xenbus/xenbus_client.c | 3 ++-
> 4 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index e420613..7fceb51 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -1134,6 +1134,8 @@ void xen_setup_shared_info(void)
> /* In UP this is as good a place as any to set up shared info */
> xen_setup_vcpu_info_placement();
> #endif
> + if (xen_pvh_domain())
> + return;
>
> xen_setup_mfn_list_list();
> }
This is another one of those cases where I think we would benefit from
introducing xen_setup_shared_info_pvh instead of adding more ifs here.
> @@ -1146,6 +1148,10 @@ void xen_setup_vcpu_info_placement(void)
> for_each_possible_cpu(cpu)
> xen_vcpu_setup(cpu);
>
> + /* PVH always uses native IRQ ops */
> + if (xen_pvh_domain())
> + return;
> +
> /* xen_vcpu_setup managed to place the vcpu_info within the
> percpu area for all cpus, so make use of it */
> if (have_vcpu_info_placement) {
Same here?
> diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
> index 0da7f86..4f7f351 100644
> --- a/arch/x86/xen/irq.c
> +++ b/arch/x86/xen/irq.c
> @@ -5,6 +5,7 @@
> #include <xen/interface/xen.h>
> #include <xen/interface/sched.h>
> #include <xen/interface/vcpu.h>
> +#include <xen/features.h>
> #include <xen/events.h>
>
> #include <asm/xen/hypercall.h>
> @@ -128,6 +129,8 @@ static const struct pv_irq_ops xen_irq_ops __initconst = {
>
> void __init xen_init_irq_ops(void)
> {
> - pv_irq_ops = xen_irq_ops;
> + /* For PVH we use default pv_irq_ops settings */
> + if (!xen_feature(XENFEAT_hvm_callback_vector))
> + pv_irq_ops = xen_irq_ops;
> x86_init.irqs.intr_init = xen_init_IRQ;
> }
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index 4035e83..627a16a 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -1922,6 +1922,11 @@ void __init xen_init_IRQ(void)
> if (xen_initial_domain())
> pci_xen_initial_domain();
>
> + if (xen_feature(XENFEAT_hvm_callback_vector)) {
> + xen_callback_vector();
> + return;
> + }
There is another call to xen_callback_vector in the if
(xen_hvm_domain()) path. Could we just move it out and have a single one
if (xen_feature(XENFEAT_hvm_callback_vector))?
> pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
> eoi_gmfn.gmfn = virt_to_mfn(pirq_eoi_map);
> rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
> diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
> index ec097d6..7f7c454 100644
> --- a/drivers/xen/xenbus/xenbus_client.c
> +++ b/drivers/xen/xenbus/xenbus_client.c
> @@ -45,6 +45,7 @@
> #include <xen/grant_table.h>
> #include <xen/xenbus.h>
> #include <xen/xen.h>
> +#include <xen/features.h>
>
> #include "xenbus_probe.h"
>
> @@ -743,7 +744,7 @@ static const struct xenbus_ring_ops ring_ops_hvm = {
>
> void __init xenbus_ring_ops_init(void)
> {
> - if (xen_pv_domain())
> + if (xen_pv_domain() && !xen_feature(XENFEAT_auto_translated_physmap))
Can we just change this test to
if (!xen_feature(XENFEAT_auto_translated_physmap))
?
> ring_ops = &ring_ops_pv;
> else
> ring_ops = &ring_ops_hvm;
> --
> 1.8.3.1
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xen.org
> http://lists.xen.org/xen-devel
>
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