[PATCH v10 08/11] xen: arch-specific hooks for domain_soft_reset()

[Vitaly Kuznetsov <vkuznets@redhat.com>]

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

ARM-specific hook is -ENOSYS for now.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
Changes since v9:
- is_hvm_domain() -> has_hvm_container_domain() to support PVH [Jan Beulich]
- introduce hvm_domain_soft_reset() to avoid making
  hvm_destroy_all_ioreq_servers() public [Jan Beulich]
- ASSERT( owner == d ) as we unconditionally do share_xen_page_with_guest()
  on domain create path [Jan Beulich]
- crash the domain when arch-specific hook fails [Jan Beulich]
- eliminate mfn_new variable [Jan Beulich]
- proper check for 'shared_info was never mapped' case.
---
 xen/arch/arm/domain.c         |  5 +++
 xen/arch/x86/domain.c         | 81 +++++++++++++++++++++++++++++++++++++++++++
 xen/arch/x86/hvm/hvm.c        |  5 +++
 xen/common/domain.c           |  7 ++++
 xen/include/asm-x86/hvm/hvm.h |  1 +
 xen/include/xen/domain.h      |  2 ++
 6 files changed, 101 insertions(+)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index b2bfc7d..5bdc2e9 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -655,6 +655,11 @@ void arch_domain_unpause(struct domain *d)
 {
 }
 
+int arch_domain_soft_reset(struct domain *d)
+{
+    return -ENOSYS;
+}
+
 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 045f6ff..afc3e1e 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -710,6 +710,87 @@ 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, gfn;
+    p2m_type_t p2mt;
+    unsigned int i;
+
+    /* Soft reset is supported for HVM/PVH domains only. */
+    if ( !has_hvm_container_domain(d) )
+        return -EINVAL;
+
+    hvm_domain_soft_reset(d);
+
+    spin_lock(&d->event_lock);
+    for ( i = 0; 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 )
+        return ret;
+
+    /*
+     * The 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);
+    ASSERT( owner == d );
+
+    mfn = page_to_mfn(page);
+    gfn = mfn_to_gmfn(d, mfn);
+
+    /*
+     * gfn == INVALID_GFN indicates that the shared_info page was never mapped
+     * to the domain's address space and there is nothing to replace.
+     */
+    if ( gfn == INVALID_GFN )
+        goto exit_put_page;
+
+    if ( mfn_x(get_gfn_query(d, gfn, &p2mt)) != mfn )
+    {
+        printk(XENLOG_G_ERR "Failed to get Dom%d's shared_info GFN (%lx)\n",
+               d->domain_id, gfn);
+        ret = -EINVAL;
+        goto exit_put_page;
+    }
+
+    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 exit_put_gfn;
+    }
+    guest_physmap_remove_page(d, gfn, mfn, PAGE_ORDER_4K);
+
+    ret = guest_physmap_add_page(d, gfn, page_to_mfn(new_page), PAGE_ORDER_4K);
+    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);
+        free_domheap_page(new_page);
+    }
+ exit_put_gfn:
+    put_gfn(d, gfn);
+ exit_put_page:
+    put_page(page);
+
+    return ret;
+}
+
 /*
  * These are the masks of CR4 bits (subject to hardware availability) which a
  * PV guest may not legitimiately attempt to modify.
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index ec1d797..2bd7f0f 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -6800,6 +6800,11 @@ bool_t altp2m_vcpu_emulate_ve(struct vcpu *v)
     return 0;
 }
 
+void hvm_domain_soft_reset(struct domain *d)
+{
+    hvm_destroy_all_ioreq_servers(d);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 4c8e6a2..ffc8740 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1066,6 +1066,13 @@ int domain_soft_reset(struct domain *d)
     for_each_vcpu ( d, v )
         unmap_vcpu_info(v);
 
+    rc = arch_domain_soft_reset(d);
+    if ( rc )
+    {
+        domain_crash(d);
+        return rc;
+    }
+
     domain_resume(d);
 
     return 0;
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 425327a..caeccf9 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -226,6 +226,7 @@ extern const struct hvm_function_table *start_vmx(void);
 int hvm_domain_initialise(struct domain *d);
 void hvm_domain_relinquish_resources(struct domain *d);
 void hvm_domain_destroy(struct domain *d);
+void hvm_domain_soft_reset(struct domain *d);
 
 int hvm_vcpu_initialise(struct vcpu *v);
 void hvm_vcpu_destroy(struct vcpu *v);
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 848db8a..a469fe0 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);
 
-- 
2.4.3