Stefano Stabellini
2012-Jan-30 16:20 UTC
[PATCH v3 0/2] use pirq_eoi_map in modern Linux kernels
Hi all, this small patch series consists of two patches: a patch for Xen and a patch for Linux. The Xen patch implements PHYSDEVOP_pirq_eoi_gmfn_v2, a new version of PHYSDEVOP_pirq_eoi_gmfn that does not change the semantics of PHYSDEVOP_eoi. The Linux patch introduces pirq_eoi_map in drivers/xen/events.c, using PHYSDEVOP_pirq_eoi_gmfn_v2. This version of the patch series addresses Konrad''s comment to the Linux patch and fixes a typo in the Xen patch. Cheers, Stefano
Stefano Stabellini
2012-Jan-30 16:21 UTC
[PATCH v3 1/2] Introduce PHYSDEVOP_pirq_eoi_gmfn_v2
PHYSDEVOP_pirq_eoi_gmfn subtly changes the semantics of PHYSDEVOP_eoi.
In order to improve the interface this patch:
- renames PHYSDEVOP_pirq_eoi_gmfn to PHYSDEVOP_pirq_eoi_gmfn_v1;
- introduces PHYSDEVOP_pirq_eoi_gmfn_v2, that is like
PHYSDEVOP_pirq_eoi_gmfn_v1 but it doesn''t modify the behaviour of
another hypercall;
- bump __XEN_LATEST_INTERFACE_VERSION__;
- #define PHYSDEVOP_pirq_eoi_gmfn to PHYSDEVOP_pirq_eoi_gmfn_v1 or
PHYSDEVOP_pirq_eoi_gmfn_v2 depending on the __XEN_INTERFACE_VERSION.
Changes in v3:
- fix a typo (__XEN_INTERFACE_VERSION instead of
__XEN_INTERFACE_VERSION__).
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
xen/arch/ia64/xen/domain.c | 1 +
xen/arch/ia64/xen/hypercall.c | 7 +++++--
xen/arch/x86/domain.c | 1 +
xen/arch/x86/physdev.c | 7 +++++--
xen/include/asm-ia64/domain.h | 3 +++
xen/include/asm-x86/domain.h | 3 +++
xen/include/public/physdev.h | 16 +++++++++++++++-
xen/include/public/xen-compat.h | 2 +-
8 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/xen/arch/ia64/xen/domain.c b/xen/arch/ia64/xen/domain.c
index 1ea5a90..a31bd32 100644
--- a/xen/arch/ia64/xen/domain.c
+++ b/xen/arch/ia64/xen/domain.c
@@ -1731,6 +1731,7 @@ int domain_relinquish_resources(struct domain *d)
if (d->arch.pirq_eoi_map != NULL) {
put_page(virt_to_page(d->arch.pirq_eoi_map));
d->arch.pirq_eoi_map = NULL;
+ d->arch.auto_unmask = 0;
}
/* Tear down shadow mode stuff. */
diff --git a/xen/arch/ia64/xen/hypercall.c b/xen/arch/ia64/xen/hypercall.c
index 130675e..18930bf 100644
--- a/xen/arch/ia64/xen/hypercall.c
+++ b/xen/arch/ia64/xen/hypercall.c
@@ -65,7 +65,7 @@ static long __do_pirq_guest_eoi(struct domain *d, int pirq)
{
if ( pirq < 0 || pirq >= NR_IRQS )
return -EINVAL;
- if ( d->arch.pirq_eoi_map ) {
+ if ( d->arch.auto_unmask ) {
spin_lock(&d->event_lock);
evtchn_unmask(pirq_to_evtchn(d, pirq));
spin_unlock(&d->event_lock);
@@ -508,7 +508,8 @@ long do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
break;
}
- case PHYSDEVOP_pirq_eoi_gmfn: {
+ case PHYSDEVOP_pirq_eoi_gmfn_v1:
+ case PHYSDEVOP_pirq_eoi_gmfn_v2: {
struct physdev_pirq_eoi_gmfn info;
unsigned long mfn;
@@ -531,6 +532,8 @@ long do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
}
current->domain->arch.pirq_eoi_map = mfn_to_virt(mfn);
+ if ( cmd == PHYSDEVOP_pirq_eoi_gmfn_v1 )
+ current->domain->arch.auto_unmask = 1;
ret = 0;
break;
}
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 61d83c8..a540af7 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -2125,6 +2125,7 @@ int domain_relinquish_resources(struct domain *d)
put_page_and_type(
mfn_to_page(d->arch.pv_domain.pirq_eoi_map_mfn));
d->arch.pv_domain.pirq_eoi_map = NULL;
+ d->arch.pv_domain.auto_unmask = 0;
}
}
diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index f280c28..df92cc7 100644
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -271,7 +271,7 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
break;
}
if ( !is_hvm_domain(v->domain) &&
- v->domain->arch.pv_domain.pirq_eoi_map )
+ v->domain->arch.pv_domain.auto_unmask )
evtchn_unmask(pirq->evtchn);
if ( !is_hvm_domain(v->domain) ||
domain_pirq_to_irq(v->domain, eoi.irq) > 0 )
@@ -293,7 +293,8 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
break;
}
- case PHYSDEVOP_pirq_eoi_gmfn: {
+ case PHYSDEVOP_pirq_eoi_gmfn_v2:
+ case PHYSDEVOP_pirq_eoi_gmfn_v1: {
struct physdev_pirq_eoi_gmfn info;
unsigned long mfn;
@@ -329,6 +330,8 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
ret = -ENOSPC;
break;
}
+ if ( cmd == PHYSDEVOP_pirq_eoi_gmfn_v1 )
+ v->domain->arch.pv_domain.auto_unmask = 1;
put_gfn(current->domain, info.gmfn);
ret = 0;
diff --git a/xen/include/asm-ia64/domain.h b/xen/include/asm-ia64/domain.h
index 12dc3bd..31d7d32 100644
--- a/xen/include/asm-ia64/domain.h
+++ b/xen/include/asm-ia64/domain.h
@@ -186,6 +186,9 @@ struct arch_domain {
/* Shared page for notifying that explicit PIRQ EOI is required. */
unsigned long *pirq_eoi_map;
unsigned long pirq_eoi_map_mfn;
+ /* set auto_unmask to 1 if you want PHYSDEVOP_eoi to automatically
+ * unmask the event channel */
+ bool_t auto_unmask;
/* Address of efi_runtime_services_t (placed in domain memory) */
void *efi_runtime;
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 00bbaeb..fb2cfd2 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -231,6 +231,9 @@ struct pv_domain
/* Shared page for notifying that explicit PIRQ EOI is required. */
unsigned long *pirq_eoi_map;
unsigned long pirq_eoi_map_mfn;
+ /* set auto_unmask to 1 if you want PHYSDEVOP_eoi to automatically
+ * unmask the event channel */
+ bool_t auto_unmask;
/* Pseudophysical e820 map (XENMEM_memory_map). */
spinlock_t e820_lock;
diff --git a/xen/include/public/physdev.h b/xen/include/public/physdev.h
index 6e23295..b78eeba 100644
--- a/xen/include/public/physdev.h
+++ b/xen/include/public/physdev.h
@@ -49,7 +49,15 @@ DEFINE_XEN_GUEST_HANDLE(physdev_eoi_t);
* will automatically get unmasked. The page registered is used as a bit
* array indexed by Xen''s PIRQ value.
*/
-#define PHYSDEVOP_pirq_eoi_gmfn 17
+#define PHYSDEVOP_pirq_eoi_gmfn_v1 17
+/*
+ * Register a shared page for the hypervisor to indicate whether the
+ * guest must issue PHYSDEVOP_eoi. This hypercall is very similar to
+ * PHYSDEVOP_pirq_eoi_gmfn_v1 but it doesn''t change the semantics of
+ * PHYSDEVOP_eoi. The page registered is used as a bit array indexed by
+ * Xen''s PIRQ value.
+ */
+#define PHYSDEVOP_pirq_eoi_gmfn_v2 28
struct physdev_pirq_eoi_gmfn {
/* IN */
xen_pfn_t gmfn;
@@ -325,6 +333,12 @@ DEFINE_XEN_GUEST_HANDLE(physdev_pci_device_t);
#define PHYSDEVOP_IRQ_NEEDS_UNMASK_NOTIFY XENIRQSTAT_needs_eoi
#define PHYSDEVOP_IRQ_SHARED XENIRQSTAT_shared
+#if __XEN_INTERFACE_VERSION__ < 0x00040200
+#define PHYSDEVOP_pirq_eoi_gmfn PHYSDEVOP_pirq_eoi_gmfn_v1
+#else
+#define PHYSDEVOP_pirq_eoi_gmfn PHYSDEVOP_pirq_eoi_gmfn_v2
+#endif
+
#endif /* __XEN_PUBLIC_PHYSDEV_H__ */
/*
diff --git a/xen/include/public/xen-compat.h b/xen/include/public/xen-compat.h
index 2e38003..d8c55bf 100644
--- a/xen/include/public/xen-compat.h
+++ b/xen/include/public/xen-compat.h
@@ -27,7 +27,7 @@
#ifndef __XEN_PUBLIC_XEN_COMPAT_H__
#define __XEN_PUBLIC_XEN_COMPAT_H__
-#define __XEN_LATEST_INTERFACE_VERSION__ 0x0003020a
+#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040200
#if defined(__XEN__) || defined(__XEN_TOOLS__)
/* Xen is built with matching headers and implements the latest interface. */
--
1.7.2.5
The pirq_eoi_map is a bitmap offered by Xen to check which pirqs need to
be EOI''d without having to issue an hypercall every time.
We use PHYSDEVOP_pirq_eoi_gmfn_v2 to map the bitmap, then if we
succeed we use pirq_eoi_map to check whether pirqs need eoi.
Changes in v3:
- explicitly use PHYSDEVOP_pirq_eoi_gmfn_v2 rather than
PHYSDEVOP_pirq_eoi_gmfn;
- introduce pirq_check_eoi_map, a function to check if a pirq needs an
eoi using the map;
-rename pirq_needs_eoi into pirq_needs_eoi_flag;
- introduce a function pointer called pirq_needs_eoi that is going to be
set to the right implementation depending on the availability of
PHYSDEVOP_pirq_eoi_gmfn_v2.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
drivers/xen/events.c | 26 +++++++++++++++++++++++---
include/xen/interface/physdev.h | 21 +++++++++++++++++++++
2 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6e075cd..cc5fc40 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -37,6 +37,7 @@
#include <asm/idle.h>
#include <asm/io_apic.h>
#include <asm/sync_bitops.h>
+#include <asm/xen/page.h>
#include <asm/xen/pci.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
@@ -108,6 +109,8 @@ struct irq_info {
#define PIRQ_SHAREABLE (1 << 1)
static int *evtchn_to_irq;
+static unsigned long *pirq_eoi_map;
+static bool (*pirq_needs_eoi)(unsigned irq);
static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
cpu_evtchn_mask);
@@ -268,10 +271,14 @@ static unsigned int cpu_from_evtchn(unsigned int evtchn)
return ret;
}
-static bool pirq_needs_eoi(unsigned irq)
+static bool pirq_check_eoi_map(unsigned irq)
{
- struct irq_info *info = info_for_irq(irq);
+ return test_bit(irq, pirq_eoi_map);
+}
+static bool pirq_needs_eoi_flag(unsigned irq)
+{
+ struct irq_info *info = info_for_irq(irq);
BUG_ON(info->type != IRQT_PIRQ);
return info->u.pirq.flags & PIRQ_NEEDS_EOI;
@@ -1693,7 +1700,7 @@ void xen_callback_vector(void) {}
void __init xen_init_IRQ(void)
{
- int i;
+ int i, rc;
evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
GFP_KERNEL);
@@ -1707,6 +1714,8 @@ void __init xen_init_IRQ(void)
for (i = 0; i < NR_EVENT_CHANNELS; i++)
mask_evtchn(i);
+ pirq_needs_eoi = pirq_needs_eoi_flag;
+
if (xen_hvm_domain()) {
xen_callback_vector();
native_init_IRQ();
@@ -1714,8 +1723,19 @@ void __init xen_init_IRQ(void)
* __acpi_register_gsi can point at the right function */
pci_xen_hvm_init();
} else {
+ 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);
+ if (rc != 0) {
+ free_page((unsigned long) pirq_eoi_map);
+ pirq_eoi_map = NULL;
+ } else
+ pirq_needs_eoi = pirq_check_eoi_map;
}
}
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index c1080d9..1775722 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -39,6 +39,27 @@ struct physdev_eoi {
};
/*
+ * Register a shared page for the hypervisor to indicate whether the guest
+ * must issue PHYSDEVOP_eoi. The semantics of PHYSDEVOP_eoi change slightly
+ * once the guest used this function in that the associated event channel
+ * will automatically get unmasked. The page registered is used as a bit
+ * array indexed by Xen''s PIRQ value.
+ */
+#define PHYSDEVOP_pirq_eoi_gmfn_v1 17
+/*
+ * Register a shared page for the hypervisor to indicate whether the
+ * guest must issue PHYSDEVOP_eoi. This hypercall is very similar to
+ * PHYSDEVOP_pirq_eoi_gmfn_v1 but it doesn''t change the semantics of
+ * PHYSDEVOP_eoi. The page registered is used as a bit array indexed by
+ * Xen''s PIRQ value.
+ */
+#define PHYSDEVOP_pirq_eoi_gmfn_v2 28
+struct physdev_pirq_eoi_gmfn {
+ /* IN */
+ unsigned long gmfn;
+};
+
+/*
* Query the status of an IRQ line.
* @arg == pointer to physdev_irq_status_query structure.
*/
--
1.7.2.5