[PATCH V1 13/16] xen/ioreq: Make x86's invalidate qemu mapcache handling common

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

As the IOREQ is a common feature now and we also need to
invalidate qemu mapcache on XENMEM_decrease_reservation on Arm
this patch moves this handling to the common code and move per-domain
qemu_mapcache_invalidate variable out of the arch sub-struct.

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

---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

Changes RFC -> V1:
   - move send_invalidate_req() to the common code
   - update patch subject/description
   - move qemu_mapcache_invalidate out of the arch sub-struct,
     update checks
   - remove #if defined(CONFIG_ARM64) from the common code
---
---
 xen/arch/arm/traps.c             |  6 ++++++
 xen/arch/x86/hvm/hypercall.c     |  9 ++++-----
 xen/arch/x86/hvm/io.c            | 14 --------------
 xen/common/ioreq.c               | 14 ++++++++++++++
 xen/common/memory.c              |  5 +++++
 xen/include/asm-x86/hvm/domain.h |  1 -
 xen/include/asm-x86/hvm/io.h     |  1 -
 xen/include/xen/ioreq.h          |  2 ++
 xen/include/xen/sched.h          |  2 ++
 9 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 6b37ae1..de48b2f 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1490,6 +1490,12 @@ static void do_trap_hypercall(struct cpu_user_regs *regs, register_t *nr,
     /* Ensure the hypercall trap instruction is re-executed. */
     if ( current->hcall_preempted )
         regs->pc -= 4;  /* re-execute 'hvc #XEN_HYPERCALL_TAG' */
+
+#ifdef CONFIG_IOREQ_SERVER
+    if ( unlikely(current->domain->qemu_mapcache_invalidate) &&
+         test_and_clear_bool(current->domain->qemu_mapcache_invalidate) )
+        send_invalidate_req();
+#endif
 }
 
 void arch_hypercall_tasklet_result(struct vcpu *v, long res)
diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index b6ccaf4..45fc20b 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -18,8 +18,10 @@
  *
  * Copyright (c) 2017 Citrix Systems Ltd.
  */
+
 #include <xen/lib.h>
 #include <xen/hypercall.h>
+#include <xen/ioreq.h>
 #include <xen/nospec.h>
 
 #include <asm/hvm/emulate.h>
@@ -46,9 +48,6 @@ static long hvm_memory_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     else
         rc = compat_memory_op(cmd, arg);
 
-    if ( (cmd & MEMOP_CMD_MASK) == XENMEM_decrease_reservation )
-        curr->domain->arch.hvm.qemu_mapcache_invalidate = true;
-
     return rc;
 }
 
@@ -329,8 +328,8 @@ int hvm_hypercall(struct cpu_user_regs *regs)
     if ( curr->hcall_preempted )
         return HVM_HCALL_preempted;
 
-    if ( unlikely(currd->arch.hvm.qemu_mapcache_invalidate) &&
-         test_and_clear_bool(currd->arch.hvm.qemu_mapcache_invalidate) )
+    if ( unlikely(currd->qemu_mapcache_invalidate) &&
+         test_and_clear_bool(currd->qemu_mapcache_invalidate) )
         send_invalidate_req();
 
     return HVM_HCALL_completed;
diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 14f8c89..e659a53 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -64,20 +64,6 @@ void send_timeoffset_req(unsigned long timeoff)
         gprintk(XENLOG_ERR, "Unsuccessful timeoffset update\n");
 }
 
-/* Ask ioemu mapcache to invalidate mappings. */
-void send_invalidate_req(void)
-{
-    ioreq_t p = {
-        .type = IOREQ_TYPE_INVALIDATE,
-        .size = 4,
-        .dir = IOREQ_WRITE,
-        .data = ~0UL, /* flush all */
-    };
-
-    if ( hvm_broadcast_ioreq(&p, false) != 0 )
-        gprintk(XENLOG_ERR, "Unsuccessful map-cache invalidate\n");
-}
-
 bool hvm_emulate_one_insn(hvm_emulate_validate_t *validate, const char *descr)
 {
     struct hvm_emulate_ctxt ctxt;
diff --git a/xen/common/ioreq.c b/xen/common/ioreq.c
index 4c3a835..e24a481 100644
--- a/xen/common/ioreq.c
+++ b/xen/common/ioreq.c
@@ -34,6 +34,20 @@
 #include <public/hvm/ioreq.h>
 #include <public/hvm/params.h>
 
+/* Ask ioemu mapcache to invalidate mappings. */
+void send_invalidate_req(void)
+{
+    ioreq_t p = {
+        .type = IOREQ_TYPE_INVALIDATE,
+        .size = 4,
+        .dir = IOREQ_WRITE,
+        .data = ~0UL, /* flush all */
+    };
+
+    if ( hvm_broadcast_ioreq(&p, false) != 0 )
+        gprintk(XENLOG_ERR, "Unsuccessful map-cache invalidate\n");
+}
+
 static void set_ioreq_server(struct domain *d, unsigned int id,
                              struct hvm_ioreq_server *s)
 {
diff --git a/xen/common/memory.c b/xen/common/memory.c
index 78781f1..9d98252 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -1651,6 +1651,11 @@ long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
     }
 
+#ifdef CONFIG_IOREQ_SERVER
+    if ( op == XENMEM_decrease_reservation )
+        curr_d->qemu_mapcache_invalidate = true;
+#endif
+
     return rc;
 }
 
diff --git a/xen/include/asm-x86/hvm/domain.h b/xen/include/asm-x86/hvm/domain.h
index 79e0afb..11d5cc1 100644
--- a/xen/include/asm-x86/hvm/domain.h
+++ b/xen/include/asm-x86/hvm/domain.h
@@ -131,7 +131,6 @@ struct hvm_domain {
 
     struct viridian_domain *viridian;
 
-    bool_t                 qemu_mapcache_invalidate;
     bool_t                 is_s3_suspended;
 
     /*
diff --git a/xen/include/asm-x86/hvm/io.h b/xen/include/asm-x86/hvm/io.h
index fb64294..3da0136 100644
--- a/xen/include/asm-x86/hvm/io.h
+++ b/xen/include/asm-x86/hvm/io.h
@@ -97,7 +97,6 @@ bool relocate_portio_handler(
     unsigned int size);
 
 void send_timeoffset_req(unsigned long timeoff);
-void send_invalidate_req(void);
 bool handle_mmio_with_translation(unsigned long gla, unsigned long gpfn,
                                   struct npfec);
 bool handle_pio(uint16_t port, unsigned int size, int dir);
diff --git a/xen/include/xen/ioreq.h b/xen/include/xen/ioreq.h
index 25ce4c2..5ade9b0 100644
--- a/xen/include/xen/ioreq.h
+++ b/xen/include/xen/ioreq.h
@@ -97,6 +97,8 @@ static inline bool hvm_ioreq_needs_completion(const ioreq_t *ioreq)
            (ioreq->type != IOREQ_TYPE_PIO || ioreq->dir != IOREQ_WRITE);
 }
 
+void send_invalidate_req(void);
+
 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);
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index ac53519..4c52a04 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -512,6 +512,8 @@ struct domain
     /* Argo interdomain communication support */
     struct argo_domain *argo;
 #endif
+
+    bool_t qemu_mapcache_invalidate;
 };
 
 static inline struct page_list_head *page_to_list(
-- 
2.7.4