From: Roger Pau Monné <roger.pau@citrix.com>
Date: Mon, 11 Aug 2014 12:58:40 +0000 (+0200)
Subject: x86/HVM: expose that grant table mappings update the IOMMU
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~4540
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=b074b99c34f9ab5bf234b4778a417b5b55690060;p=xen.git

x86/HVM: expose that grant table mappings update the IOMMU

Add a new CPUID flag for leaf 4 that indicates that grant/foreign
mappings update the IOMMU accordingly.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index d2c6942b64..d40c48ed7e 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -67,6 +67,7 @@
 #include <asm/mem_access.h>
 #include <public/mem_event.h>
 #include <xen/rangeset.h>
+#include <public/arch-x86/cpuid.h>
 
 bool_t __read_mostly hvm_enabled;
 
@@ -4197,6 +4198,15 @@ void hvm_hypervisor_cpuid_leaf(uint32_t sub_idx,
     *eax = *ebx = *ecx = *edx = 0;
     if ( hvm_funcs.hypervisor_cpuid_leaf )
         hvm_funcs.hypervisor_cpuid_leaf(sub_idx, eax, ebx, ecx, edx);
+
+    if ( sub_idx == 0 )
+    {
+        /*
+         * Indicate that memory mapped from other domains (either grants or
+         * foreign pages) has valid IOMMU entries.
+         */
+        *eax |= XEN_HVM_CPUID_IOMMU_MAPPINGS;
+    }
 }
 
 void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx,
diff --git a/xen/include/public/arch-x86/cpuid.h b/xen/include/public/arch-x86/cpuid.h
index 7135d5456b..e57a4578e5 100644
--- a/xen/include/public/arch-x86/cpuid.h
+++ b/xen/include/public/arch-x86/cpuid.h
@@ -73,6 +73,8 @@
 /* EAX Features */
 #define XEN_HVM_CPUID_APIC_ACCESS_VIRT (1u << 0) /* Virtualized APIC registers */
 #define XEN_HVM_CPUID_X2APIC_VIRT      (1u << 1) /* Virtualized x2APIC accesses */
+/* Memory mapped from other domains has valid IOMMU entries */
+#define XEN_HVM_CPUID_IOMMU_MAPPINGS   (1u << 2)
 
 #define XEN_CPUID_MAX_NUM_LEAVES 4