Commit 2771374d authored by Mukesh Rathor's avatar Mukesh Rathor Committed by Konrad Rzeszutek Wilk
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xen/pvh: Piggyback on PVHVM for event channels (v2) 



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.

We will piggyback on how the event channel mechanism is
used in PVHVM - that is we want the normal native IRQ mechanism
and we will install a vector (hvm callback) for which we
will call the event channel mechanism.

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: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Acked-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
parent 9103bb0f

arch/x86/xen/enlighten.c

+3 −2
Original line number Diff line number Diff line
@@ -1144,8 +1144,9 @@ void xen_setup_vcpu_info_placement(void) 
		xen_vcpu_setup(cpu);



	/* 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) {

	 * percpu area for all cpus, so make use of it. Note that for

	 * PVH we want to use native IRQ mechanism. */

	if (have_vcpu_info_placement && !xen_pvh_domain()) {

		pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);

		pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);

		pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);

arch/x86/xen/irq.c

+4 −1
Original line number Diff line number Diff line
@@ -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)

{

	/* 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;

}

drivers/xen/events/events_base.c

+9 −5
Original line number Diff line number Diff line
@@ -1685,8 +1685,15 @@ void __init xen_init_IRQ(void) 
	pirq_needs_eoi = pirq_needs_eoi_flag;



#ifdef CONFIG_X86

	if (xen_hvm_domain()) {

	if (xen_pv_domain()) {

		irq_ctx_init(smp_processor_id());

		if (xen_initial_domain())

			pci_xen_initial_domain();

	}

	if (xen_feature(XENFEAT_hvm_callback_vector))

		xen_callback_vector();



	if (xen_hvm_domain()) {

		native_init_IRQ();

		/* pci_xen_hvm_init must be called after native_init_IRQ so that

		 * __acpi_register_gsi can point at the right function */
@@ -1695,13 +1702,10 @@ void __init xen_init_IRQ(void) 
		int rc;

		struct physdev_pirq_eoi_gmfn eoi_gmfn;



		irq_ctx_init(smp_processor_id());

		if (xen_initial_domain())

			pci_xen_initial_domain();



		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);

		/* TODO: No PVH support for PIRQ EOI */

		if (rc != 0) {

			free_page((unsigned long) pirq_eoi_map);

			pirq_eoi_map = NULL;

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