[v4,10/28] x86/vvtd: Enable Interrupt Remapping through GCMD

Commit Message

Chao Gao Nov. 17, 2017, 6:22 a.m. UTC

Software writes this field to enable/disable interrupt reampping. This
patch emulate IRES field of GCMD. Currently, Guest's whole IRT are
mapped to Xen permanently for the latency of delivering interrupt. And
the old mapping is undone if present when trying to set up a new one.

Signed-off-by: Chao Gao <[e-mail]>
Signed-off-by: Lan Tianyu <[e-mail]>
---
v4:
 - map guest's interrupt reampping table to Xen permanently rather than
 mapping one specific page on demand.
---
 xen/drivers/passthrough/vtd/iommu.h |  3 +-
 xen/drivers/passthrough/vtd/vvtd.c  | 98 +++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+), 1 deletion(-)

Patch

diff --git a/xen/drivers/passthrough/vtd/iommu.h b/xen/drivers/passthrough/vtd/iommu.h
index 8579843..9c59aeb 100644
--- a/xen/drivers/passthrough/vtd/iommu.h
+++ b/xen/drivers/passthrough/vtd/iommu.h
@@ -161,9 +161,10 @@ 
 #define DMA_GSTS_AFLS   (((u64)1) << 28)
 #define DMA_GSTS_WBFS   (((u64)1) << 27)
 #define DMA_GSTS_QIES   (((u64)1) <<26)
+#define DMA_GSTS_IRES_SHIFT     25
+#define DMA_GSTS_IRES   (((u64)1) << DMA_GSTS_IRES_SHIFT)
 #define DMA_GSTS_SIRTPS_SHIFT   24
 #define DMA_GSTS_SIRTPS (((u64)1) << DMA_GSTS_SIRTPS_SHIFT)
-#define DMA_GSTS_IRES   (((u64)1) <<25)
 #define DMA_GSTS_CFIS   (((u64)1) <<23)
 
 /* IRTA_REG */
diff --git a/xen/drivers/passthrough/vtd/vvtd.c b/xen/drivers/passthrough/vtd/vvtd.c
index f0476fe..06e522a 100644
--- a/xen/drivers/passthrough/vtd/vvtd.c
+++ b/xen/drivers/passthrough/vtd/vvtd.c
@@ -24,6 +24,7 @@ 
 #include <xen/xmalloc.h>
 #include <asm/current.h>
 #include <asm/hvm/domain.h>
+#include <asm/p2m.h>
 
 #include "iommu.h"
 
@@ -37,6 +38,7 @@ 
 
 struct hvm_hw_vvtd {
     bool eim_enabled;
+    bool intremap_enabled;
 
     /* Interrupt remapping table base gfn and the max of entries */
     uint16_t irt_max_entry;
@@ -52,6 +54,7 @@  struct vvtd {
     struct domain *domain;
 
     struct hvm_hw_vvtd hw;
+    void *irt_base;
 };
 
 /* Setting viommu_verbose enables debugging messages of vIOMMU */
@@ -118,6 +121,77 @@  static void *domain_vvtd(const struct domain *d)
         return NULL;
 }
 
+static void *map_guest_pages(struct domain *d, uint64_t gfn, uint32_t nr)
+{
+    mfn_t *mfn = xmalloc_array(mfn_t, nr);
+    void* ret;
+    int i;
+
+    if ( !mfn )
+        return NULL;
+
+    for ( i = 0; i < nr; i++)
+    {
+        struct page_info *p = get_page_from_gfn(d, gfn + i, NULL, P2M_ALLOC);
+
+        if ( !p || !get_page_type(p, PGT_writable_page) )
+        {
+            if ( p )
+                put_page(p);
+            goto undo;
+        }
+
+        mfn[i] = _mfn(page_to_mfn(p));
+    }
+
+    ret = vmap(mfn, nr);
+    if ( ret == NULL )
+        goto undo;
+    xfree(mfn);
+
+    return ret;
+
+ undo:
+    for ( ; --i >= 0; )
+        put_page_and_type(mfn_to_page(mfn_x(mfn[i])));
+    xfree(mfn);
+    gprintk(XENLOG_ERR, "Failed to map guest pages %lx nr %x\n", gfn, nr);
+
+    return NULL;
+}
+
+static void unmap_guest_pages(void *va, uint32_t nr)
+{
+    unsigned long *mfn = xmalloc_array(unsigned long, nr);
+    int i;
+    void *va_copy = va;
+
+    if ( !mfn )
+    {
+        printk("%s %d: No free memory\n", __FILE__, __LINE__);
+        return;
+    }
+
+    for ( i = 0; i < nr; i++, va += PAGE_SIZE)
+        mfn[i] = domain_page_map_to_mfn(va);
+
+    vunmap(va_copy);
+
+    for ( i = 0; i < nr; i++)
+        put_page_and_type(mfn_to_page(mfn[i]));
+}
+
+static void write_gcmd_ire(struct vvtd *vvtd, uint32_t val)
+{
+    bool set = val & DMA_GCMD_IRE;
+
+    vvtd_info("%sable Interrupt Remapping\n", set ? "En" : "Dis");
+
+    vvtd->hw.intremap_enabled = set;
+    (set ? vvtd_set_bit : vvtd_clear_bit)
+        (vvtd, DMAR_GSTS_REG, DMA_GSTS_IRES_SHIFT);
+}
+
 static void write_gcmd_sirtp(struct vvtd *vvtd, uint32_t val)
 {
     uint64_t irta = vvtd_get_reg_quad(vvtd, DMAR_IRTA_REG);
@@ -131,16 +205,29 @@  static void write_gcmd_sirtp(struct vvtd *vvtd, uint32_t val)
      * the 'Set Interrupt Remap Table Pointer' operation.
      */
     vvtd_clear_bit(vvtd, DMAR_GSTS_REG, DMA_GSTS_SIRTPS_SHIFT);
+    if ( vvtd->hw.intremap_enabled )
+        vvtd_info("Update Interrupt Remapping Table when active\n");
 
     if ( gfn_x(vvtd->hw.irt) != PFN_DOWN(DMA_IRTA_ADDR(irta)) ||
          vvtd->hw.irt_max_entry != DMA_IRTA_SIZE(irta) )
     {
+        if ( vvtd->irt_base )
+        {
+            unmap_guest_pages(vvtd->irt_base,
+                              PFN_UP(vvtd->hw.irt_max_entry *
+                                     sizeof(struct iremap_entry)));
+            vvtd->irt_base = NULL;
+        }
         vvtd->hw.irt = _gfn(PFN_DOWN(DMA_IRTA_ADDR(irta)));
         vvtd->hw.irt_max_entry = DMA_IRTA_SIZE(irta);
         vvtd->hw.eim_enabled = !!(irta & IRTA_EIME);
         vvtd_info("Update IR info (addr=%lx eim=%d size=%d)\n",
                   gfn_x(vvtd->hw.irt), vvtd->hw.eim_enabled,
                   vvtd->hw.irt_max_entry);
+
+        vvtd->irt_base = map_guest_pages(vvtd->domain, gfn_x(vvtd->hw.irt),
+                                         PFN_UP(vvtd->hw.irt_max_entry *
+                                                sizeof(struct iremap_entry)));
     }
     vvtd_set_bit(vvtd, DMAR_GSTS_REG, DMA_GSTS_SIRTPS_SHIFT);
 }
@@ -162,6 +249,8 @@  static void vvtd_write_gcmd(struct vvtd *vvtd, uint32_t val)
 
     if ( changed & DMA_GCMD_SIRTP )
         write_gcmd_sirtp(vvtd, val);
+    if ( changed & DMA_GCMD_IRE )
+        write_gcmd_ire(vvtd, val);
 }
 
 static int vvtd_in_range(struct vcpu *v, unsigned long addr)
@@ -278,7 +367,16 @@  static int vvtd_destroy(struct viommu *viommu)
     struct vvtd *vvtd = viommu->priv;
 
     if ( vvtd )
+    {
+        if ( vvtd->irt_base )
+        {
+            unmap_guest_pages(vvtd->irt_base,
+                              PFN_UP(vvtd->hw.irt_max_entry *
+                                     sizeof(struct iremap_entry)));
+            vvtd->irt_base = NULL;
+        }
         xfree(vvtd);
+    }
 
     return 0;
 }