[xen master] x86/iommu: introduce a cache sync hook

[patchbot@xxxxxxx]

commit 91526b460e5009fc56edbd6809e66c327281faba
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Tue Jul 7 14:38:34 2020 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Jul 7 14:38:34 2020 +0200

    x86/iommu: introduce a cache sync hook
    
    The hook is only implemented for VT-d and it uses the already existing
    iommu_sync_cache function present in VT-d code. The new hook is
    added so that the cache can be flushed by code outside of VT-d when
    using shared page tables.
    
    Note that alloc_pgtable_maddr must use the now locally defined
    sync_cache function, because IOMMU ops are not yet setup the first
    time the function gets called during IOMMU initialization.
    
    No functional change intended.
    
    This is part of XSA-321.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/drivers/passthrough/vtd/extern.h | 1 -
 xen/drivers/passthrough/vtd/iommu.c  | 5 +++--
 xen/include/asm-x86/iommu.h          | 7 +++++++
 xen/include/xen/iommu.h              | 1 +
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/extern.h 
b/xen/drivers/passthrough/vtd/extern.h
index 52b5e1c60d..f15947af1f 100644
--- a/xen/drivers/passthrough/vtd/extern.h
+++ b/xen/drivers/passthrough/vtd/extern.h
@@ -43,7 +43,6 @@ void disable_qinval(struct vtd_iommu *iommu);
 int enable_intremap(struct vtd_iommu *iommu, int eim);
 void disable_intremap(struct vtd_iommu *iommu);
 
-void iommu_sync_cache(const void *addr, unsigned int size);
 int iommu_alloc(struct acpi_drhd_unit *drhd);
 void iommu_free(struct acpi_drhd_unit *drhd);
 
diff --git a/xen/drivers/passthrough/vtd/iommu.c 
b/xen/drivers/passthrough/vtd/iommu.c
index 55eb140033..93bcd72f84 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -147,7 +147,7 @@ static int context_get_domain_id(struct context_entry 
*context,
 
 static int iommus_incoherent;
 
-void iommu_sync_cache(const void *addr, unsigned int size)
+static void sync_cache(const void *addr, unsigned int size)
 {
     int i;
     static unsigned int clflush_size = 0;
@@ -180,7 +180,7 @@ uint64_t alloc_pgtable_maddr(unsigned long npages, nodeid_t 
node)
         vaddr = __map_domain_page(cur_pg);
         memset(vaddr, 0, PAGE_SIZE);
 
-        iommu_sync_cache(vaddr, PAGE_SIZE);
+        sync_cache(vaddr, PAGE_SIZE);
         unmap_domain_page(vaddr);
         cur_pg++;
     }
@@ -2778,6 +2778,7 @@ const struct iommu_ops __initconstrel intel_iommu_ops = {
     .iotlb_flush_all = iommu_flush_iotlb_all,
     .get_reserved_device_memory = intel_iommu_get_reserved_device_memory,
     .dump_p2m_table = vtd_dump_p2m_table,
+    .sync_cache = sync_cache,
 };
 
 const struct iommu_init_ops __initconstrel intel_iommu_init_ops = {
diff --git a/xen/include/asm-x86/iommu.h b/xen/include/asm-x86/iommu.h
index 85741f7c96..864e025078 100644
--- a/xen/include/asm-x86/iommu.h
+++ b/xen/include/asm-x86/iommu.h
@@ -121,6 +121,13 @@ extern bool untrusted_msi;
 int pi_update_irte(const struct pi_desc *pi_desc, const struct pirq *pirq,
                    const uint8_t gvec);
 
+#define iommu_sync_cache(addr, size) ({                 \
+    const struct iommu_ops *ops = iommu_get_ops();      \
+                                                        \
+    if ( ops->sync_cache )                              \
+        iommu_vcall(ops, sync_cache, addr, size);       \
+})
+
 #endif /* !__ARCH_X86_IOMMU_H__ */
 /*
  * Local variables:
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 6264d3d07f..3272874958 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -275,6 +275,7 @@ struct iommu_ops {
     int (*setup_hpet_msi)(struct msi_desc *);
 
     int (*adjust_irq_affinities)(void);
+    void (*sync_cache)(const void *addr, unsigned int size);
 #endif /* CONFIG_X86 */
 
     int __must_check (*suspend)(void);
--
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