x86/ioreq: Prepare IOREQ feature for making it common

As a lot of x86 code can be re-used on Arm later on, this
patch makes some preparation to x86/hvm/ioreq.c before moving
to the common code. This way we will get a verbatim copy
for a code movement in subsequent patch.

This patch mostly introduces specific hooks to abstract arch
specific materials taking into the account the requirment to leave
the "legacy" mechanism of mapping magic pages for the IOREQ servers
x86 specific and not expose it to the common code.

These hooks are named according to the more consistent new naming
scheme right away (including dropping the "hvm" prefixes and infixes):
- IOREQ server functions should start with "ioreq_server_"
- IOREQ functions should start with "ioreq_"
other functions will be renamed in subsequent patches.

It worth mentioning that a code which checks the return value of
p2m_set_ioreq_server() in hvm_map_mem_type_to_ioreq_server() was
folded into arch_ioreq_server_map_mem_type() for the clear split.
So the p2m_change_entry_type_global() is called with ioreq_server
lock held.

Also re-order #include-s alphabetically.

This support is going to be used on Arm to be able run device
emulator outside of Xen hypervisor.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
CC: Julien Grall <julien.grall@arm.com>

Message-Id: <1606732298-22107-2-git-send-email-olekstysh@gmail.com>

2 files changed, 133 insertions, 60 deletions

diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
index 1cc27df87f..e3dfb490f3 100644
--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -17,15 +17,15 @@
  */
 
 #include <xen/ctype.h>
+#include <xen/domain.h>
+#include <xen/event.h>
 #include <xen/init.h>
+#include <xen/irq.h>
 #include <xen/lib.h>
-#include <xen/trace.h>
+#include <xen/paging.h>
 #include <xen/sched.h>
-#include <xen/irq.h>
 #include <xen/softirq.h>
-#include <xen/domain.h>
-#include <xen/event.h>
-#include <xen/paging.h>
+#include <xen/trace.h>
 #include <xen/vpci.h>
 
 #include <asm/hvm/emulate.h>
@@ -170,6 +170,29 @@ static bool hvm_wait_for_io(struct hvm_ioreq_vcpu *sv, ioreq_t *p)
     return true;
 }
 
+bool arch_vcpu_ioreq_completion(enum hvm_io_completion io_completion)
+{
+    switch ( io_completion )
+    {
+    case HVMIO_realmode_completion:
+    {
+        struct hvm_emulate_ctxt ctxt;
+
+        hvm_emulate_init_once(&ctxt, NULL, guest_cpu_user_regs());
+        vmx_realmode_emulate_one(&ctxt);
+        hvm_emulate_writeback(&ctxt);
+
+        break;
+    }
+
+    default:
+        ASSERT_UNREACHABLE();
+        break;
+    }
+
+    return true;
+}
+
 bool handle_hvm_io_completion(struct vcpu *v)
 {
     struct domain *d = v->domain;
@@ -209,19 +232,8 @@ bool handle_hvm_io_completion(struct vcpu *v)
         return handle_pio(vio->io_req.addr, vio->io_req.size,
                           vio->io_req.dir);
 
-    case HVMIO_realmode_completion:
-    {
-        struct hvm_emulate_ctxt ctxt;
-
-        hvm_emulate_init_once(&ctxt, NULL, guest_cpu_user_regs());
-        vmx_realmode_emulate_one(&ctxt);
-        hvm_emulate_writeback(&ctxt);
-
-        break;
-    }
     default:
-        ASSERT_UNREACHABLE();
-        break;
+        return arch_vcpu_ioreq_completion(io_completion);
     }
 
     return true;
@@ -477,9 +489,6 @@ static void hvm_update_ioreq_evtchn(struct hvm_ioreq_server *s,
     }
 }
 
-#define HANDLE_BUFIOREQ(s) \
-    ((s)->bufioreq_handling != HVM_IOREQSRV_BUFIOREQ_OFF)
-
 static int hvm_ioreq_server_add_vcpu(struct hvm_ioreq_server *s,
                                      struct vcpu *v)
 {
@@ -586,7 +595,7 @@ static void hvm_ioreq_server_remove_all_vcpus(struct hvm_ioreq_server *s)
     spin_unlock(&s->lock);
 }
 
-static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s)
+int arch_ioreq_server_map_pages(struct hvm_ioreq_server *s)
 {
     int rc;
 
@@ -601,7 +610,7 @@ static int hvm_ioreq_server_map_pages(struct hvm_ioreq_server *s)
     return rc;
 }
 
-static void hvm_ioreq_server_unmap_pages(struct hvm_ioreq_server *s)
+void arch_ioreq_server_unmap_pages(struct hvm_ioreq_server *s)
 {
     hvm_unmap_ioreq_gfn(s, true);
     hvm_unmap_ioreq_gfn(s, false);
@@ -674,6 +683,12 @@ static int hvm_ioreq_server_alloc_rangesets(struct hvm_ioreq_server *s,
     return rc;
 }
 
+void arch_ioreq_server_enable(struct hvm_ioreq_server *s)
+{
+    hvm_remove_ioreq_gfn(s, false);
+    hvm_remove_ioreq_gfn(s, true);
+}
+
 static void hvm_ioreq_server_enable(struct hvm_ioreq_server *s)
 {
     struct hvm_ioreq_vcpu *sv;
@@ -683,8 +698,7 @@ static void hvm_ioreq_server_enable(struct hvm_ioreq_server *s)
     if ( s->enabled )
         goto done;
 
-    hvm_remove_ioreq_gfn(s, false);
-    hvm_remove_ioreq_gfn(s, true);
+    arch_ioreq_server_enable(s);
 
     s->enabled = true;
 
@@ -697,6 +711,12 @@ static void hvm_ioreq_server_enable(struct hvm_ioreq_server *s)
     spin_unlock(&s->lock);
 }
 
+void arch_ioreq_server_disable(struct hvm_ioreq_server *s)
+{
+    hvm_add_ioreq_gfn(s, true);
+    hvm_add_ioreq_gfn(s, false);
+}
+
 static void hvm_ioreq_server_disable(struct hvm_ioreq_server *s)
 {
     spin_lock(&s->lock);
@@ -704,8 +724,7 @@ static void hvm_ioreq_server_disable(struct hvm_ioreq_server *s)
     if ( !s->enabled )
         goto done;
 
-    hvm_add_ioreq_gfn(s, true);
-    hvm_add_ioreq_gfn(s, false);
+    arch_ioreq_server_disable(s);
 
     s->enabled = false;
 
@@ -750,7 +769,7 @@ static int hvm_ioreq_server_init(struct hvm_ioreq_server *s,
 
  fail_add:
     hvm_ioreq_server_remove_all_vcpus(s);
-    hvm_ioreq_server_unmap_pages(s);
+    arch_ioreq_server_unmap_pages(s);
 
     hvm_ioreq_server_free_rangesets(s);
 
@@ -764,7 +783,7 @@ static void hvm_ioreq_server_deinit(struct hvm_ioreq_server *s)
     hvm_ioreq_server_remove_all_vcpus(s);
 
     /*
-     * NOTE: It is safe to call both hvm_ioreq_server_unmap_pages() and
+     * NOTE: It is safe to call both arch_ioreq_server_unmap_pages() and
      *       hvm_ioreq_server_free_pages() in that order.
      *       This is because the former will do nothing if the pages
      *       are not mapped, leaving the page to be freed by the latter.
@@ -772,7 +791,7 @@ static void hvm_ioreq_server_deinit(struct hvm_ioreq_server *s)
      *       the page_info pointer to NULL, meaning the latter will do
      *       nothing.
      */
-    hvm_ioreq_server_unmap_pages(s);
+    arch_ioreq_server_unmap_pages(s);
     hvm_ioreq_server_free_pages(s);
 
     hvm_ioreq_server_free_rangesets(s);
@@ -836,6 +855,12 @@ int hvm_create_ioreq_server(struct domain *d, int bufioreq_handling,
     return rc;
 }
 
+/* Called when target domain is paused */
+void arch_ioreq_server_destroy(struct hvm_ioreq_server *s)
+{
+    p2m_set_ioreq_server(s->target, 0, s);
+}
+
 int hvm_destroy_ioreq_server(struct domain *d, ioservid_t id)
 {
     struct hvm_ioreq_server *s;
@@ -855,7 +880,7 @@ int hvm_destroy_ioreq_server(struct domain *d, ioservid_t id)
 
     domain_pause(d);
 
-    p2m_set_ioreq_server(d, 0, s);
+    arch_ioreq_server_destroy(s);
 
     hvm_ioreq_server_disable(s);
 
@@ -900,7 +925,7 @@ int hvm_get_ioreq_server_info(struct domain *d, ioservid_t id,
 
     if ( ioreq_gfn || bufioreq_gfn )
     {
-        rc = hvm_ioreq_server_map_pages(s);
+        rc = arch_ioreq_server_map_pages(s);
         if ( rc )
             goto out;
     }
@@ -1080,6 +1105,24 @@ int hvm_unmap_io_range_from_ioreq_server(struct domain *d, ioservid_t id,
     return rc;
 }
 
+/* Called with ioreq_server lock held */
+int arch_ioreq_server_map_mem_type(struct domain *d,
+                                   struct hvm_ioreq_server *s,
+                                   uint32_t flags)
+{
+    int rc = p2m_set_ioreq_server(d, flags, s);
+
+    if ( rc == 0 && flags == 0 )
+    {
+        const struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+        if ( read_atomic(&p2m->ioreq.entry_count) )
+            p2m_change_entry_type_global(d, p2m_ioreq_server, p2m_ram_rw);
+    }
+
+    return rc;
+}
+
 /*
  * Map or unmap an ioreq server to specific memory type. For now, only
  * HVMMEM_ioreq_server is supported, and in the future new types can be
@@ -1112,19 +1155,11 @@ int hvm_map_mem_type_to_ioreq_server(struct domain *d, ioservid_t id,
     if ( s->emulator != current->domain )
         goto out;
 
-    rc = p2m_set_ioreq_server(d, flags, s);
+    rc = arch_ioreq_server_map_mem_type(d, s, flags);
 
  out:
     spin_unlock_recursive(&d->arch.hvm.ioreq_server.lock);
 
-    if ( rc == 0 && flags == 0 )
-    {
-        struct p2m_domain *p2m = p2m_get_hostp2m(d);
-
-        if ( read_atomic(&p2m->ioreq.entry_count) )
-            p2m_change_entry_type_global(d, p2m_ioreq_server, p2m_ram_rw);
-    }
-
     return rc;
 }
 
@@ -1210,12 +1245,17 @@ void hvm_all_ioreq_servers_remove_vcpu(struct domain *d, struct vcpu *v)
     spin_unlock_recursive(&d->arch.hvm.ioreq_server.lock);
 }
 
+bool arch_ioreq_server_destroy_all(struct domain *d)
+{
+    return relocate_portio_handler(d, 0xcf8, 0xcf8, 4);
+}
+
 void hvm_destroy_all_ioreq_servers(struct domain *d)
 {
     struct hvm_ioreq_server *s;
     unsigned int id;
 
-    if ( !relocate_portio_handler(d, 0xcf8, 0xcf8, 4) )
+    if ( !arch_ioreq_server_destroy_all(d) )
         return;
 
     spin_lock_recursive(&d->arch.hvm.ioreq_server.lock);
@@ -1239,33 +1279,28 @@ void hvm_destroy_all_ioreq_servers(struct domain *d)
     spin_unlock_recursive(&d->arch.hvm.ioreq_server.lock);
 }
 
-struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
-                                                 ioreq_t *p)
+int arch_ioreq_server_get_type_addr(const struct domain *d,
+                                    const ioreq_t *p,
+                                    uint8_t *type,
+                                    uint64_t *addr)
 {
-    struct hvm_ioreq_server *s;
-    uint32_t cf8;
-    uint8_t type;
-    uint64_t addr;
-    unsigned int id;
+    unsigned int cf8 = d->arch.hvm.pci_cf8;
 
     if ( p->type != IOREQ_TYPE_COPY && p->type != IOREQ_TYPE_PIO )
-        return NULL;
-
-    cf8 = d->arch.hvm.pci_cf8;
+        return -EINVAL;
 
     if ( p->type == IOREQ_TYPE_PIO &&
          (p->addr & ~3) == 0xcfc &&
          CF8_ENABLED(cf8) )
     {
-        uint32_t x86_fam;
+        unsigned int x86_fam, reg;
         pci_sbdf_t sbdf;
-        unsigned int reg;
 
         reg = hvm_pci_decode_addr(cf8, p->addr, &sbdf);
 
         /* PCI config data cycle */
-        type = XEN_DMOP_IO_RANGE_PCI;
-        addr = ((uint64_t)sbdf.sbdf << 32) | reg;
+        *type = XEN_DMOP_IO_RANGE_PCI;
+        *addr = ((uint64_t)sbdf.sbdf << 32) | reg;
         /* AMD extended configuration space access? */
         if ( CF8_ADDR_HI(cf8) &&
              d->arch.cpuid->x86_vendor == X86_VENDOR_AMD &&
@@ -1277,16 +1312,30 @@ struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
 
             if ( !rdmsr_safe(MSR_AMD64_NB_CFG, msr_val) &&
                  (msr_val & (1ULL << AMD64_NB_CFG_CF8_EXT_ENABLE_BIT)) )
-                addr |= CF8_ADDR_HI(cf8);
+                *addr |= CF8_ADDR_HI(cf8);
         }
     }
     else
     {
-        type = (p->type == IOREQ_TYPE_PIO) ?
-                XEN_DMOP_IO_RANGE_PORT : XEN_DMOP_IO_RANGE_MEMORY;
-        addr = p->addr;
+        *type = (p->type == IOREQ_TYPE_PIO) ?
+                 XEN_DMOP_IO_RANGE_PORT : XEN_DMOP_IO_RANGE_MEMORY;
+        *addr = p->addr;
     }
 
+    return 0;
+}
+
+struct hvm_ioreq_server *hvm_select_ioreq_server(struct domain *d,
+                                                 ioreq_t *p)
+{
+    struct hvm_ioreq_server *s;
+    uint8_t type;
+    uint64_t addr;
+    unsigned int id;
+
+    if ( arch_ioreq_server_get_type_addr(d, p, &type, &addr) )
+        return NULL;
+
     FOR_EACH_IOREQ_SERVER(d, id, s)
     {
         struct rangeset *r;
@@ -1515,11 +1564,16 @@ static int hvm_access_cf8(
     return X86EMUL_UNHANDLEABLE;
 }
 
+void arch_ioreq_domain_init(struct domain *d)
+{
+    register_portio_handler(d, 0xcf8, 4, hvm_access_cf8);
+}
+
 void hvm_ioreq_init(struct domain *d)
 {
     spin_lock_init(&d->arch.hvm.ioreq_server.lock);
 
-    register_portio_handler(d, 0xcf8, 4, hvm_access_cf8);
+    arch_ioreq_domain_init(d);
 }
 
 /*
diff --git a/xen/include/asm-x86/hvm/ioreq.h b/xen/include/asm-x86/hvm/ioreq.h
index e2588e912f..cc792855fb 100644
--- a/xen/include/asm-x86/hvm/ioreq.h
+++ b/xen/include/asm-x86/hvm/ioreq.h
@@ -19,6 +19,25 @@
 #ifndef __ASM_X86_HVM_IOREQ_H__
 #define __ASM_X86_HVM_IOREQ_H__
 
+#define HANDLE_BUFIOREQ(s) \
+    ((s)->bufioreq_handling != HVM_IOREQSRV_BUFIOREQ_OFF)
+
+bool arch_vcpu_ioreq_completion(enum hvm_io_completion io_completion);
+int arch_ioreq_server_map_pages(struct hvm_ioreq_server *s);
+void arch_ioreq_server_unmap_pages(struct hvm_ioreq_server *s);
+void arch_ioreq_server_enable(struct hvm_ioreq_server *s);
+void arch_ioreq_server_disable(struct hvm_ioreq_server *s);
+void arch_ioreq_server_destroy(struct hvm_ioreq_server *s);
+int arch_ioreq_server_map_mem_type(struct domain *d,
+                                   struct hvm_ioreq_server *s,
+                                   uint32_t flags);
+bool arch_ioreq_server_destroy_all(struct domain *d);
+int arch_ioreq_server_get_type_addr(const struct domain *d,
+                                    const ioreq_t *p,
+                                    uint8_t *type,
+                                    uint64_t *addr);
+void arch_ioreq_domain_init(struct domain *d);
+
 bool hvm_io_pending(struct vcpu *v);
 bool handle_hvm_io_completion(struct vcpu *v);
 bool is_ioreq_server_page(struct domain *d, const struct page_info *page);