[RFC PATCH V1 08/12] xen/arm: Invalidate qemu mapcache on XENMEM_decrease_reservation

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Borrow x86's logic to invalidate qemu mapcache.

TODO: Move send_invalidate_req() to common code (ioreq.c?).

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
---
 xen/arch/arm/ioreq.c            | 14 ++++++++++++++
 xen/arch/arm/traps.c            |  6 ++++++
 xen/common/memory.c             |  6 ++++++
 xen/include/asm-arm/domain.h    |  2 ++
 xen/include/asm-arm/hvm/ioreq.h |  2 ++
 5 files changed, 30 insertions(+)

diff --git a/xen/arch/arm/ioreq.c b/xen/arch/arm/ioreq.c
index a9cc839..8f60c41 100644
--- a/xen/arch/arm/ioreq.c
+++ b/xen/arch/arm/ioreq.c
@@ -75,6 +75,20 @@ bool handle_mmio(void)
     return true;
 }
 
+/* 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");
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 4cdf098..ea472d1 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->arch.hvm.qemu_mapcache_invalidate) &&
+         test_and_clear_bool(current->domain->arch.hvm.qemu_mapcache_invalidate) )
+        send_invalidate_req();
+#endif
 }
 
 void arch_hypercall_tasklet_result(struct vcpu *v, long res)
diff --git a/xen/common/memory.c b/xen/common/memory.c
index 8b306f6..8d9f0a8 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -1652,6 +1652,12 @@ long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         break;
     }
 
+    /* x86 already sets the flag in hvm_memory_op() */
+#if defined(CONFIG_ARM64) && defined(CONFIG_IOREQ_SERVER)
+    if ( op == XENMEM_decrease_reservation )
+        curr_d->arch.hvm.qemu_mapcache_invalidate = true;
+#endif
+
     return rc;
 }
 
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index e060b0a..0db8bb4 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -69,6 +69,8 @@ struct hvm_domain
         spinlock_t              lock;
         struct hvm_ioreq_server *server[MAX_NR_IOREQ_SERVERS];
     } ioreq_server;
+
+    bool_t qemu_mapcache_invalidate;
 };
 
 #ifdef CONFIG_ARM_64
diff --git a/xen/include/asm-arm/hvm/ioreq.h b/xen/include/asm-arm/hvm/ioreq.h
index 83a560c..392ce64 100644
--- a/xen/include/asm-arm/hvm/ioreq.h
+++ b/xen/include/asm-arm/hvm/ioreq.h
@@ -90,6 +90,8 @@ static inline void arch_hvm_ioreq_destroy(struct domain *d)
 #define IOREQ_IO_UNHANDLED   IO_UNHANDLED
 #define IOREQ_IO_RETRY       IO_RETRY
 
+void send_invalidate_req(void);
+
 #endif /* __ASM_X86_HVM_IOREQ_H__ */
 
 /*
-- 
2.7.4