[Xen-devel] [PATCH] ARM: Support for guest-request vm-events

[Corneliu ZUZU <czuzu@xxxxxxxxxxxxxxx>]

This patch implements ARM support for guest-request vm-events.
The code has been ported from x86 side w/ minor adjustments.

Signed-off-by: Corneliu ZUZU <czuzu@xxxxxxxxxxxxxxx>
---
 xen/arch/arm/Makefile           |   2 +
 xen/arch/arm/event.c            |  86 ++++++++++++++++++++++++++++
 xen/arch/arm/hvm.c              |   9 ++-
 xen/arch/arm/monitor.c          | 123 ++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/domain.h    |   8 +++
 xen/include/asm-arm/hvm/event.h |  36 ++++++++++++
 xen/include/asm-arm/monitor.h   |   8 +--
 xen/include/asm-arm/vm_event.h  |   4 +-
 8 files changed, 267 insertions(+), 9 deletions(-)
 create mode 100644 xen/arch/arm/event.c
 create mode 100644 xen/arch/arm/monitor.c
 create mode 100644 xen/include/asm-arm/hvm/event.h

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 2f050f5..d3d8d7b 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -31,6 +31,8 @@ obj-y += smpboot.o
 obj-y += smp.o
 obj-y += shutdown.o
 obj-y += traps.o
+obj-y += event.o
+obj-y += monitor.o
 obj-y += vgic.o vgic-v2.o
 obj-$(CONFIG_ARM_64) += vgic-v3.o
 obj-y += vtimer.o
diff --git a/xen/arch/arm/event.c b/xen/arch/arm/event.c
new file mode 100644
index 0000000..e4bc25a
--- /dev/null
+++ b/xen/arch/arm/event.c
@@ -0,0 +1,86 @@
+/*
+* arch/arm/event.c
+*
+* Common hardware virtual machine event abstractions.
+* Copy-pasted & adjusted from x86 counterpart.
+*
+* Copyright (c) 2004, Intel Corporation.
+* Copyright (c) 2005, International Business Machines Corporation.
+* Copyright (c) 2008, Citrix Systems, Inc.
+* Copyright (c) 2016, Bitdefender S.R.L.
+*
+* This program is free software; you can redistribute it and/or modify it
+* under the terms and conditions of the GNU General Public License,
+* version 2, as published by the Free Software Foundation.
+*
+* This program is distributed in the hope it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+* more details.
+*
+* You should have received a copy of the GNU General Public License along with
+* this program; If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <xen/vm_event.h>
+#include <xen/paging.h>
+#include <asm/hvm/event.h>
+#include <public/vm_event.h>
+
+static int hvm_event_traps(uint8_t sync, vm_event_request_t *req)
+{
+    int rc;
+    struct vcpu *curr = current;
+    struct domain *currd = curr->domain;
+
+    rc = vm_event_claim_slot(currd, &currd->vm_event->monitor);
+    switch ( rc )
+    {
+        case 0:
+            break;
+        case -ENOSYS:
+            /*
+             * If there was no ring to handle the event, then
+             * simply continue executing normally.
+             */
+            return 1;
+        default:
+            return rc;
+    };
+
+    if ( sync )
+    {
+        req->flags |= VM_EVENT_FLAG_VCPU_PAUSED;
+        vm_event_vcpu_pause(curr);
+    }
+
+    vm_event_put_request(currd, &currd->vm_event->monitor, req);
+
+    return 1;
+}
+
+void hvm_event_guest_request(void)
+{
+    struct vcpu *curr = current;
+    struct arch_domain *currad = &curr->domain->arch;
+
+    if ( currad->monitor.guest_request_enabled )
+    {
+        vm_event_request_t req = {
+            .reason = VM_EVENT_REASON_GUEST_REQUEST,
+            .vcpu_id = curr->vcpu_id,
+        };
+
+        hvm_event_traps(currad->monitor.guest_request_sync, &req);
+    }
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/hvm.c b/xen/arch/arm/hvm.c
index 5fd0753..f314bd7 100644
--- a/xen/arch/arm/hvm.c
+++ b/xen/arch/arm/hvm.c
@@ -11,10 +11,10 @@
 #include <public/hvm/params.h>
 #include <public/hvm/hvm_op.h>
 
+#include <asm/hvm/event.h>
 #include <asm/hypercall.h>
 
 long do_hvm_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) arg)
-
 {
     long rc = 0;
 
@@ -55,6 +55,13 @@ long do_hvm_op(unsigned long op, 
XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
     }
 
+    case HVMOP_guest_request_vm_event:
+        if ( guest_handle_is_null(arg) )
+            hvm_event_guest_request();
+        else
+            rc = -EINVAL;
+        break;
+
     default:
     {
         gdprintk(XENLOG_DEBUG, "HVMOP op=%lu: not implemented\n", op);
diff --git a/xen/arch/arm/monitor.c b/xen/arch/arm/monitor.c
new file mode 100644
index 0000000..22455f7
--- /dev/null
+++ b/xen/arch/arm/monitor.c
@@ -0,0 +1,123 @@
+/*
+ * arch/arm/monitor.c
+ *
+ * Architecture-specific monitor_op domctl handler.
+ * Copy-pasted & adjusted from x86 counterpart.
+ *
+ * Copyright (c) 2015 Tamas K Lengyel (tamas@xxxxxxxxxxxxx)
+ * Copyright (c) 2016 Bitdefender S.R.L.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <xen/sched.h>
+#include <asm/domain.h>
+#include <asm/monitor.h>
+#include <public/domctl.h>
+#include <xsm/xsm.h>
+
+/*
+ * Sanity check whether option is already enabled/disabled
+ */
+static inline
+int status_check(struct xen_domctl_monitor_op *mop, bool_t old_status)
+{
+    bool_t requested_status = (mop->op == XEN_DOMCTL_MONITOR_OP_ENABLE);
+
+    if ( old_status == requested_status )
+        return -EEXIST;
+
+    return 0;
+}
+
+static inline uint32_t get_capabilities(struct domain *d)
+{
+    uint32_t capabilities = 0;
+
+    capabilities = (1 << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST);
+
+    return capabilities;
+}
+
+int monitor_domctl(struct domain *d, struct xen_domctl_monitor_op *mop)
+{
+    int rc;
+    struct arch_domain *ad = &d->arch;
+    uint32_t capabilities = get_capabilities(d);
+
+    rc = xsm_vm_event_control(XSM_PRIV, d, mop->op, mop->event);
+    if ( rc )
+        return rc;
+
+    if ( mop->op == XEN_DOMCTL_MONITOR_OP_GET_CAPABILITIES )
+    {
+        mop->event = capabilities;
+        return 0;
+    }
+
+    /*
+     * Sanity check
+     */
+    if ( mop->op != XEN_DOMCTL_MONITOR_OP_ENABLE &&
+         mop->op != XEN_DOMCTL_MONITOR_OP_DISABLE )
+        return -EOPNOTSUPP;
+
+    /* Check if event type is available. */
+    if ( !(capabilities & (1 << mop->event)) )
+        return -EOPNOTSUPP;
+
+    switch ( mop->event )
+    {
+    case XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST:
+    {
+        bool_t old_status = ad->monitor.guest_request_enabled;
+
+        rc = status_check(mop, old_status);
+        if ( rc )
+            return rc;
+
+        ad->monitor.guest_request_sync = mop->u.guest_request.sync;
+
+        domain_pause(d);
+        ad->monitor.guest_request_enabled = !old_status;
+        domain_unpause(d);
+        break;
+    }
+
+    default:
+        /*
+         * Should not be reached unless get_capabilities() is not properly
+         * implemented. In that case, since reaching this point does not
+         * really break anything, don't crash the hypervisor, issue a
+         * warning instead of BUG().
+         */
+        printk(XENLOG_WARNING
+                "WARNING, BUG: get_capabilities() not properly"
+                "implemented.\n");
+
+        return -EOPNOTSUPP;
+    };
+
+    return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index aa7f283..cd5d285 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -124,6 +124,14 @@ struct arch_domain
     } vuart;
 
     unsigned int evtchn_irq;
+
+    /* Monitor options */
+    struct {
+        uint8_t guest_request_enabled       : 1;
+        uint8_t guest_request_sync          : 1;
+        uint8_t                             : 6;
+    } monitor;
+
 }  __cacheline_aligned;
 
 struct arch_vcpu
diff --git a/xen/include/asm-arm/hvm/event.h b/xen/include/asm-arm/hvm/event.h
new file mode 100644
index 0000000..246dfb8
--- /dev/null
+++ b/xen/include/asm-arm/hvm/event.h
@@ -0,0 +1,36 @@
+/*
+ * include/asm-arm/hvm/event.h:
+ *
+ * Copy-pasted & adjusted from x86 counterpart.
+ *
+ * Copyright (c) 2016, Bitdefender S.R.L.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_ARM_HVM_EVENT_H__
+#define __ASM_ARM_HVM_EVENT_H__
+
+void hvm_event_guest_request(void);
+
+#endif /* __ASM_ARM_HVM_EVENT_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/monitor.h b/xen/include/asm-arm/monitor.h
index a3a9703..9d1a530 100644
--- a/xen/include/asm-arm/monitor.h
+++ b/xen/include/asm-arm/monitor.h
@@ -24,10 +24,6 @@
 #include <xen/sched.h>
 #include <public/domctl.h>
 
-static inline
-int monitor_domctl(struct domain *d, struct xen_domctl_monitor_op *op)
-{
-    return -ENOSYS;
-}
+int monitor_domctl(struct domain *d, struct xen_domctl_monitor_op *op);
 
-#endif /* __ASM_X86_MONITOR_H__ */
+#endif /* __ASM_ARM_MONITOR_H__ */
diff --git a/xen/include/asm-arm/vm_event.h b/xen/include/asm-arm/vm_event.h
index 4d0fbf7..b468b89 100644
--- a/xen/include/asm-arm/vm_event.h
+++ b/xen/include/asm-arm/vm_event.h
@@ -25,14 +25,14 @@
 static inline
 int vm_event_init_domain(struct domain *d)
 {
-    /* Not supported on ARM. */
+    /* Nothing to do */
     return 0;
 }
 
 static inline
 void vm_event_cleanup_domain(struct domain *d)
 {
-    /* Not supported on ARM. */
+    memset(&d->arch.monitor, 0, sizeof(d->arch.monitor));
 }
 
 static inline
-- 
2.5.0


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