[PATCH v4 09/28] x86/vvtd: Set Interrupt Remapping Table Pointer through GCMD

[Chao Gao <chao.gao@intel.com>]

Software sets SIRTP field of GCMD to set/update the interrupt remapping
table pointer used by hardware. The interrupt remapping table pointer is
specified through the Interrupt Remapping Table Address (IRTA_REG)
register.

This patch emulates this operation and adds some new fields in VVTD to track
info (e.g. the table's gfn and max supported entries) of interrupt remapping
table.

Signed-off-by: Chao Gao <chao.gao@intel.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>

---
v4:
 - declare eim_enabled as bool and irt as gfn_t
 - rename vvtd_handle_gcmd_sirtp() to write_gcmd_sirtp()

v3:
 - ignore unaligned r/w of vt-d hardware registers and return X86EMUL_OK
---
 xen/drivers/passthrough/vtd/iommu.h | 16 ++++++-
 xen/drivers/passthrough/vtd/vvtd.c  | 86 +++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/vtd/iommu.h b/xen/drivers/passthrough/vtd/iommu.h
index f2ef3dd..8579843 100644
--- a/xen/drivers/passthrough/vtd/iommu.h
+++ b/xen/drivers/passthrough/vtd/iommu.h
@@ -48,7 +48,8 @@
 #define DMAR_IQT_REG            0x88 /* invalidation queue tail */
 #define DMAR_IQA_REG            0x90 /* invalidation queue addr */
 #define DMAR_IECTL_REG          0xa0 /* invalidation event control register */
-#define DMAR_IRTA_REG           0xb8 /* intr remap */
+#define DMAR_IRTA_REG           0xb8 /* base address of intr remap table */
+#define DMAR_IRTUA_REG          0xbc /* upper address of intr remap table */
 
 #define OFFSET_STRIDE        (9)
 #define dmar_readl(dmar, reg) readl((dmar) + (reg))
@@ -150,6 +151,9 @@
 #define DMA_GCMD_SIRTP  (((u64)1) << 24)
 #define DMA_GCMD_CFI    (((u64)1) << 23)
 
+/* mask of one-shot bits */
+#define DMA_GCMD_ONE_SHOT_MASK 0x96ffffff
+
 /* GSTS_REG */
 #define DMA_GSTS_TES    (((u64)1) << 31)
 #define DMA_GSTS_RTPS   (((u64)1) << 30)
@@ -157,10 +161,18 @@
 #define DMA_GSTS_AFLS   (((u64)1) << 28)
 #define DMA_GSTS_WBFS   (((u64)1) << 27)
 #define DMA_GSTS_QIES   (((u64)1) <<26)
+#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_SIRTPS (((u64)1) << 24)
 #define DMA_GSTS_CFIS   (((u64)1) <<23)
 
+/* IRTA_REG */
+/* The base of 4KB aligned interrupt remapping table */
+#define DMA_IRTA_ADDR(val)      ((val) & ~0xfffULL)
+/* The size of remapping table is 2^(x+1), where x is the size field in IRTA */
+#define DMA_IRTA_S(val)         (val & 0xf)
+#define DMA_IRTA_SIZE(val)      (1UL << (DMA_IRTA_S(val) + 1))
+
 /* PMEN_REG */
 #define DMA_PMEN_EPM    (((u32)1) << 31)
 #define DMA_PMEN_PRS    (((u32)1) << 0)
diff --git a/xen/drivers/passthrough/vtd/vvtd.c b/xen/drivers/passthrough/vtd/vvtd.c
index d78d878..f0476fe 100644
--- a/xen/drivers/passthrough/vtd/vvtd.c
+++ b/xen/drivers/passthrough/vtd/vvtd.c
@@ -36,6 +36,12 @@
 #define VVTD_MAX_OFFSET VVTD_FRCD_END
 
 struct hvm_hw_vvtd {
+    bool eim_enabled;
+
+    /* Interrupt remapping table base gfn and the max of entries */
+    uint16_t irt_max_entry;
+    gfn_t irt;
+
     uint32_t regs[VVTD_MAX_OFFSET/sizeof(uint32_t)];
 };
 
@@ -73,6 +79,16 @@ boolean_runtime_param("viommu_verbose", viommu_verbose);
 
 #define VVTD_REG_POS(vvtd, offset) &(vvtd->hw.regs[offset/sizeof(uint32_t)])
 
+static inline void vvtd_set_bit(struct vvtd *vvtd, uint32_t reg, int nr)
+{
+    __set_bit(nr, VVTD_REG_POS(vvtd, reg));
+}
+
+static inline void vvtd_clear_bit(struct vvtd *vvtd, uint32_t reg, int nr)
+{
+    __clear_bit(nr, VVTD_REG_POS(vvtd, reg));
+}
+
 static inline void vvtd_set_reg(struct vvtd *vvtd, uint32_t reg, uint32_t value)
 {
     *VVTD_REG_POS(vvtd, reg) = value;
@@ -102,6 +118,52 @@ static void *domain_vvtd(const struct domain *d)
         return NULL;
 }
 
+static void write_gcmd_sirtp(struct vvtd *vvtd, uint32_t val)
+{
+    uint64_t irta = vvtd_get_reg_quad(vvtd, DMAR_IRTA_REG);
+
+    if ( !(val & DMA_GCMD_SIRTP) )
+        return;
+
+    /*
+     * Hardware clears this bit when software sets the SIRTPS field in
+     * the Global Command register and sets it when hardware completes
+     * the 'Set Interrupt Remap Table Pointer' operation.
+     */
+    vvtd_clear_bit(vvtd, DMAR_GSTS_REG, DMA_GSTS_SIRTPS_SHIFT);
+
+    if ( gfn_x(vvtd->hw.irt) != PFN_DOWN(DMA_IRTA_ADDR(irta)) ||
+         vvtd->hw.irt_max_entry != DMA_IRTA_SIZE(irta) )
+    {
+        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_set_bit(vvtd, DMAR_GSTS_REG, DMA_GSTS_SIRTPS_SHIFT);
+}
+
+static void vvtd_write_gcmd(struct vvtd *vvtd, uint32_t val)
+{
+    uint32_t orig = vvtd_get_reg(vvtd, DMAR_GSTS_REG);
+    uint32_t changed;
+
+    orig = orig & DMA_GCMD_ONE_SHOT_MASK;   /* reset the one-shot bits */
+    changed = orig ^ val;
+
+    if ( !changed )
+        return;
+
+    if ( changed & (changed - 1) )
+        vvtd_info("Write %x to GCMD (current %x), updating multiple fields",
+                  val, orig);
+
+    if ( changed & DMA_GCMD_SIRTP )
+        write_gcmd_sirtp(vvtd, val);
+}
+
 static int vvtd_in_range(struct vcpu *v, unsigned long addr)
 {
     struct vvtd *vvtd = domain_vvtd(v->domain);
@@ -139,6 +201,30 @@ static int vvtd_write(struct vcpu *v, unsigned long addr,
 
     vvtd_info("Write offset %x len %d val %lx\n", offset, len, val);
 
+    if ( (len != 4 && len != 8) || (offset & (len - 1)) )
+        return X86EMUL_OKAY;
+
+    switch ( offset )
+    {
+    case DMAR_GCMD_REG:
+        vvtd_write_gcmd(vvtd, val);
+        break;
+
+    case DMAR_IRTA_REG:
+        vvtd_set_reg(vvtd, offset, val);
+        if ( len == 4 )
+            break;
+        val = val >> 32;
+        offset += 4;
+        /* Fall through */
+    case DMAR_IRTUA_REG:
+        vvtd_set_reg(vvtd, offset, val);
+        break;
+
+    default:
+        break;
+    }
+
     return X86EMUL_OKAY;
 }
 
-- 
1.8.3.1


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