[Xen-devel] [PATCH RFC 4/4] xen: arch-specific hooks for domain_soft_reset()

[Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>]

x86-specific hook cleans up the pirq-emuirq mappings and replaces the
shared_info frame with an empty page to support subsequent
XENMAPSPACE_shared_info call.

ARM-specific hook is a noop for now.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 xen/arch/arm/domain.c    |  5 ++++
 xen/arch/x86/domain.c    | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
 xen/common/domain.c      |  2 ++
 xen/include/xen/domain.h |  2 ++
 4 files changed, 82 insertions(+)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 24b8938..c112afa 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -653,6 +653,11 @@ void arch_domain_unpause(struct domain *d)
 {
 }
 
+int arch_domain_soft_reset(struct domain *d)
+{
+    return 0;
+}
+
 static int is_guest_pv32_psr(uint32_t psr)
 {
     switch (psr & PSR_MODE_MASK)
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 1f1550e..2d23c17 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -679,6 +679,79 @@ void arch_domain_unpause(struct domain *d)
         viridian_time_ref_count_thaw(d);
 }
 
+int arch_domain_soft_reset(struct domain *d)
+{
+    struct page_info *page = virt_to_page(d->shared_info), *new_page;
+    int ret = 0;
+    struct domain *owner;
+    unsigned long mfn, mfn_new, gfn;
+    p2m_type_t __p2mt;
+
+    if ( is_hvm_domain(d) )
+    {
+        int i;
+
+        spin_lock(&d->event_lock);
+        for ( i = 1; i < d->nr_pirqs ; i ++ )
+            if ( domain_pirq_to_emuirq(d, i) != IRQ_UNBOUND )
+            {
+                ret = unmap_domain_pirq_emuirq(d, i);
+                if (ret)
+                    break;
+            }
+        spin_unlock(&d->event_lock);
+    }
+
+    if ( ret || !d->shared_info || !page )
+        return ret;
+
+    /*
+     * shared_info page needs to be replaced with a new page, otherwise we
+     * will get a hole if the domain does XENMAPSPACE_shared_info
+     */
+
+    owner = page_get_owner_and_reference(page);
+    if ( owner != d )
+    {
+        put_page(page);
+        return 0;
+    }
+
+    mfn = page_to_mfn(page);
+    if ( !mfn_valid(mfn) )
+    {
+        printk(XENLOG_G_ERR "Dom%d's shared_info page points to invalid MFN\n",
+               d->domain_id);
+        ret = -EINVAL;
+        goto fail_put_page;
+    }
+
+    gfn = mfn_to_gmfn(d, mfn);
+    get_gfn_query(d, gfn, &__p2mt);
+
+    new_page = alloc_domheap_page(d, 0);
+    if ( !new_page )
+    {
+        printk(XENLOG_G_ERR "Failed to alloc a page to replace"
+               " Dom%d's shared_info frame %lx\n", d->domain_id, gfn);
+        ret = -ENOMEM;
+        goto fail_put_gfn;
+    }
+    mfn_new = page_to_mfn(new_page);
+    guest_physmap_remove_page(d, gfn, mfn, 0);
+
+    ret = guest_physmap_add_page(d, gfn, mfn_new, 0);
+    if ( ret )
+        printk(XENLOG_G_ERR "Failed to add a page to replace"
+               " Dom%d's shared_info frame %lx\n", d->domain_id, gfn);
+ fail_put_gfn:
+    put_gfn(d, gfn);
+ fail_put_page:
+    put_page(page);
+
+    return ret;
+}
+
 unsigned long pv_guest_cr4_fixup(const struct vcpu *v, unsigned long guest_cr4)
 {
     unsigned long hv_cr4_mask, hv_cr4 = real_cr4_to_pv_guest_cr4(read_cr4());
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 44e532b..0ab1a71 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1467,6 +1467,8 @@ int domain_soft_reset(struct domain *d)
     for_each_vcpu ( d, v )
             unmap_vcpu_info(v);
 
+    ret = arch_domain_soft_reset(d);
+
  vcpu_unpause:
     for_each_vcpu ( d, v )
         if ( v != current )
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 57f8ddd..311bead 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -65,6 +65,8 @@ void arch_domain_shutdown(struct domain *d);
 void arch_domain_pause(struct domain *d);
 void arch_domain_unpause(struct domain *d);
 
+int arch_domain_soft_reset(struct domain *d);
+
 int arch_set_info_guest(struct vcpu *, vcpu_guest_context_u);
 void arch_get_info_guest(struct vcpu *, vcpu_guest_context_u);
 
-- 
1.9.3


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