[PATCH v2 03/27] ARM: GICv3 ITS: allocate device and collection table

[Andre Przywara <andre.przywara@arm.com>]

Each ITS maps a pair of a DeviceID (for instance derived from a PCI
b/d/f triplet) and an EventID (the MSI payload or interrupt ID) to a
pair of LPI number and collection ID, which points to the target CPU.
This mapping is stored in the device and collection tables, which software
has to provide for the ITS to use.
Allocate the required memory and hand it to the ITS.
The maximum number of devices is limited to a compile-time constant
exposed in Kconfig.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 docs/misc/xen-command-line.markdown |   8 ++
 xen/arch/arm/Kconfig                |  14 ++++
 xen/arch/arm/gic-v3-its.c           | 163 ++++++++++++++++++++++++++++++++++++
 xen/arch/arm/gic-v3.c               |   3 +
 xen/include/asm-arm/gic_v3_its.h    |  63 +++++++++++++-
 5 files changed, 250 insertions(+), 1 deletion(-)

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 619016d..068d116 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -1158,6 +1158,14 @@ based interrupts. Any higher IRQs will be available for use via PCI MSI.
 ### maxcpus
 > `= <integer>`
 
+### max\_its\_device\_bits
+> `= <integer>`
+
+Specifies the maximum number of devices using MSIs on the ARM GICv3 ITS
+controller to allocate table entries for. Each table entry uses a hardware
+specific size, typically 8 or 16 bytes.
+Defaults to 10 bits (to cover at most 1024 devices).
+
 ### max\_lpi\_bits
 > `= <integer>`
 
diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 86f7b53..0d50156 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -64,6 +64,20 @@ config MAX_PHYS_LPI_BITS
           This can be overridden on the command line with the max_lpi_bits
           parameter.
 
+config MAX_PHYS_ITS_DEVICE_BITS
+        depends on HAS_ITS
+        int "Number of device bits the ITS supports"
+        range 1 32
+        default "10"
+        help
+          Specifies the maximum number of devices which want to use the ITS.
+          Xen needs to allocates memory for the whole range very early.
+          The allocation scheme may be sparse, so a much larger number must
+          be supported to cover devices with a high bus number or those on
+          separate bus segments.
+          This can be overridden on the command line with the
+          max_its_device_bits parameter.
+
 endmenu
 
 menu "ARM errata workaround via the alternative framework"
diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index 4056e5b..9982fe9 100644
--- a/xen/arch/arm/gic-v3-its.c
+++ b/xen/arch/arm/gic-v3-its.c
@@ -19,8 +19,10 @@
  */
 
 #include <xen/lib.h>
+#include <xen/mm.h>
 #include <asm/gic_v3_defs.h>
 #include <asm/gic_v3_its.h>
+#include <asm/io.h>
 
 LIST_HEAD(host_its_list);
 
@@ -29,6 +31,167 @@ bool gicv3_its_host_has_its(void)
     return !list_empty(&host_its_list);
 }
 
+#define BASER_ATTR_MASK                                           \
+        ((0x3UL << GITS_BASER_SHAREABILITY_SHIFT)               | \
+         (0x7UL << GITS_BASER_OUTER_CACHEABILITY_SHIFT)         | \
+         (0x7UL << GITS_BASER_INNER_CACHEABILITY_SHIFT))
+#define BASER_RO_MASK   (GENMASK(58, 56) | GENMASK(52, 48))
+
+/* Check that the physical address can be encoded in the PROPBASER register. */
+static bool check_propbaser_phys_addr(void *vaddr, unsigned int page_bits)
+{
+    paddr_t paddr = virt_to_maddr(vaddr);
+
+    return (!(paddr & ~GENMASK(page_bits < 16 ? 47 : 51, page_bits)));
+}
+
+static uint64_t encode_propbaser_phys_addr(paddr_t addr, unsigned int page_bits)
+{
+    uint64_t ret = addr & GENMASK(47, page_bits);
+
+    if ( page_bits < 16 )
+        return ret;
+
+    /* For 64K pages address bits 51-48 are encoded in bits 15-12. */
+    return ret | ((addr & GENMASK(51, 48)) >> (48 - 12));
+}
+
+/* The ITS BASE registers work with page sizes of 4K, 16K or 64K. */
+#define BASER_PAGE_BITS(sz) ((sz) * 2 + 12)
+
+static int its_map_baser(void __iomem *basereg, uint64_t regc,
+                         unsigned int nr_items)
+{
+    uint64_t attr, reg;
+    unsigned int entry_size = GITS_BASER_ENTRY_SIZE(regc);
+    unsigned int pagesz = 2, order, table_size;
+    void *buffer;
+
+    attr  = GIC_BASER_InnerShareable << GITS_BASER_SHAREABILITY_SHIFT;
+    attr |= GIC_BASER_CACHE_SameAsInner << GITS_BASER_OUTER_CACHEABILITY_SHIFT;
+    attr |= GIC_BASER_CACHE_RaWaWb << GITS_BASER_INNER_CACHEABILITY_SHIFT;
+
+    /*
+     * Setup the BASE register with the attributes that we like. Then read
+     * it back and see what sticks (page size, cacheability and shareability
+     * attributes), retrying if necessary.
+     */
+retry:
+    table_size = ROUNDUP(nr_items * entry_size, BIT(BASER_PAGE_BITS(pagesz)));
+    /* The BASE registers support at most 256 pages. */
+    table_size = min(table_size, 256U << BASER_PAGE_BITS(pagesz));
+    /* The memory block must be aligned to the requested page size. */
+    order = max(get_order_from_bytes(table_size), pagesz * 2);
+
+    buffer = alloc_xenheap_pages(order, 0);
+    if ( !buffer )
+        return -ENOMEM;
+
+    if ( !check_propbaser_phys_addr(buffer, BASER_PAGE_BITS(pagesz)) )
+    {
+        free_xenheap_pages(buffer, 0);
+        return -ERANGE;
+    }
+    memset(buffer, 0, table_size);
+
+    reg  = attr;
+    reg |= (pagesz << GITS_BASER_PAGE_SIZE_SHIFT);
+    reg |= (table_size >> BASER_PAGE_BITS(pagesz)) - 1;
+    reg |= regc & BASER_RO_MASK;
+    reg |= GITS_VALID_BIT;
+    reg |= encode_propbaser_phys_addr(virt_to_maddr(buffer),
+                                      BASER_PAGE_BITS(pagesz));
+
+    writeq_relaxed(reg, basereg);
+    regc = readq_relaxed(basereg);
+
+    /* The host didn't like our attributes, just use what it returned. */
+    if ( (regc & BASER_ATTR_MASK) != attr )
+    {
+        /* If we can't map it shareable, drop cacheability as well. */
+        if ( (regc & GITS_BASER_SHAREABILITY_MASK) == GIC_BASER_NonShareable )
+        {
+            regc &= ~GITS_BASER_INNER_CACHEABILITY_MASK;
+            writeq_relaxed(regc, basereg);
+        }
+        attr = regc & BASER_ATTR_MASK;
+    }
+    if ( (regc & GITS_BASER_INNER_CACHEABILITY_MASK) <= GIC_BASER_CACHE_nC )
+        clean_and_invalidate_dcache_va_range(buffer, table_size);
+
+    /* If the host accepted our page size, we are done. */
+    if ( ((regc >> GITS_BASER_PAGE_SIZE_SHIFT) & 0x3UL) == pagesz )
+        return 0;
+
+    free_xenheap_pages(buffer, order);
+
+    if ( pagesz-- > 0 )
+        goto retry;
+
+    /* None of the page sizes was accepted, give up */
+    return -EINVAL;
+}
+
+static unsigned int max_its_device_bits = CONFIG_MAX_PHYS_ITS_DEVICE_BITS;
+integer_param("max_its_device_bits", max_its_device_bits);
+
+static int gicv3_its_init_single_its(struct host_its *hw_its)
+{
+    uint64_t reg;
+    int i;
+    unsigned int devid_bits;
+
+    hw_its->its_base = ioremap_nocache(hw_its->addr, hw_its->size);
+    if ( !hw_its->its_base )
+        return -ENOMEM;
+
+    reg = readq_relaxed(hw_its->its_base + GITS_TYPER);
+    devid_bits = GITS_TYPER_DEVICE_ID_BITS(reg);
+    devid_bits = min(devid_bits, max_its_device_bits);
+
+    for ( i = 0; i < GITS_BASER_NR_REGS; i++ )
+    {
+        void __iomem *basereg = hw_its->its_base + GITS_BASER0 + i * 8;
+        unsigned int type;
+
+        reg = readq_relaxed(basereg);
+        type = (reg & GITS_BASER_TYPE_MASK) >> GITS_BASER_TYPE_SHIFT;
+        switch ( type )
+        {
+        case GITS_BASER_TYPE_NONE:
+            continue;
+        case GITS_BASER_TYPE_DEVICE:
+            its_map_baser(basereg, reg, BIT(devid_bits));
+            break;
+        case GITS_BASER_TYPE_COLLECTION:
+            its_map_baser(basereg, reg, NR_CPUS);
+            break;
+        /* In case this is a GICv4, provide a (dummy) vPE table as well. */
+        case GITS_BASER_TYPE_VCPU:
+            its_map_baser(basereg, reg, 1);
+            break;
+        default:
+            continue;
+        }
+    }
+
+    return 0;
+}
+
+int gicv3_its_init(void)
+{
+    struct host_its *hw_its;
+    int ret;
+
+    list_for_each_entry(hw_its, &host_its_list, entry) {
+        ret = gicv3_its_init_single_its(hw_its);
+        if ( ret )
+            return ret;
+    }
+
+    return 0;
+}
+
 /* Scan the DT for any ITS nodes and create a list of host ITSes out of it. */
 void gicv3_its_dt_init(const struct dt_device_node *node)
 {
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index ed78363..cc1e219 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1590,6 +1590,9 @@ static int __init gicv3_init(void)
     spin_lock(&gicv3.lock);
 
     gicv3_dist_init();
+    res = gicv3_its_init();
+    if ( res )
+        printk(XENLOG_WARNING "GICv3: ITS: initialization failed: %d\n", res);
     res = gicv3_cpu_init();
     gicv3_hyp_init();
 
diff --git a/xen/include/asm-arm/gic_v3_its.h b/xen/include/asm-arm/gic_v3_its.h
index 219d109..a6c0acc 100644
--- a/xen/include/asm-arm/gic_v3_its.h
+++ b/xen/include/asm-arm/gic_v3_its.h
@@ -20,6 +20,60 @@
 #ifndef __ASM_ARM_ITS_H__
 #define __ASM_ARM_ITS_H__
 
+#define GITS_CTLR                       0x000
+#define GITS_IIDR                       0x004
+#define GITS_TYPER                      0x008
+#define GITS_CBASER                     0x080
+#define GITS_CWRITER                    0x088
+#define GITS_CREADR                     0x090
+#define GITS_BASER_NR_REGS              8
+#define GITS_BASER0                     0x100
+#define GITS_BASER1                     0x108
+#define GITS_BASER2                     0x110
+#define GITS_BASER3                     0x118
+#define GITS_BASER4                     0x120
+#define GITS_BASER5                     0x128
+#define GITS_BASER6                     0x130
+#define GITS_BASER7                     0x138
+
+/* Register bits */
+#define GITS_VALID_BIT                  BIT_ULL(63)
+
+#define GITS_CTLR_QUIESCENT             BIT(31)
+#define GITS_CTLR_ENABLE                BIT(0)
+
+#define GITS_TYPER_DEVIDS_SHIFT         13
+#define GITS_TYPER_DEVIDS_MASK          (0x1fUL << GITS_TYPER_DEVIDS_SHIFT)
+#define GITS_TYPER_DEVICE_ID_BITS(r)    (((r & GITS_TYPER_DEVIDS_MASK) >> \
+                                               GITS_TYPER_DEVIDS_SHIFT) + 1)
+
+#define GITS_IIDR_VALUE                 0x34c
+
+#define GITS_BASER_INDIRECT             BIT_ULL(62)
+#define GITS_BASER_INNER_CACHEABILITY_SHIFT        59
+#define GITS_BASER_TYPE_SHIFT           56
+#define GITS_BASER_TYPE_MASK            (7ULL << GITS_BASER_TYPE_SHIFT)
+#define GITS_BASER_OUTER_CACHEABILITY_SHIFT        53
+#define GITS_BASER_TYPE_NONE            0UL
+#define GITS_BASER_TYPE_DEVICE          1UL
+#define GITS_BASER_TYPE_VCPU            2UL
+#define GITS_BASER_TYPE_CPU             3UL
+#define GITS_BASER_TYPE_COLLECTION      4UL
+#define GITS_BASER_TYPE_RESERVED5       5UL
+#define GITS_BASER_TYPE_RESERVED6       6UL
+#define GITS_BASER_TYPE_RESERVED7       7UL
+#define GITS_BASER_ENTRY_SIZE_SHIFT     48
+#define GITS_BASER_ENTRY_SIZE(reg)                                       \
+                        (((reg >> GITS_BASER_ENTRY_SIZE_SHIFT) & 0x1f) + 1)
+#define GITS_BASER_SHAREABILITY_SHIFT   10
+#define GITS_BASER_PAGE_SIZE_SHIFT      8
+#define GITS_BASER_RO_MASK              (GITS_BASER_TYPE_MASK | \
+                                        (31UL << GITS_BASER_ENTRY_SIZE_SHIFT) |\
+                                        GITS_BASER_INDIRECT)
+#define GITS_BASER_SHAREABILITY_MASK   (0x3ULL << GITS_BASER_SHAREABILITY_SHIFT)
+#define GITS_BASER_OUTER_CACHEABILITY_MASK   (0x7ULL << GITS_BASER_OUTER_CACHEABILITY_SHIFT)
+#define GITS_BASER_INNER_CACHEABILITY_MASK   (0x7ULL << GITS_BASER_INNER_CACHEABILITY_SHIFT)
+
 #include <xen/device_tree.h>
 
 /* data structure for each hardware ITS */
@@ -28,6 +82,7 @@ struct host_its {
     const struct dt_device_node *dt_node;
     paddr_t addr;
     paddr_t size;
+    void __iomem *its_base;
 };
 
 
@@ -42,8 +97,9 @@ bool gicv3_its_host_has_its(void);
 
 int gicv3_lpi_init_rdist(void __iomem * rdist_base);
 
-/* Initialize the host structures for LPIs. */
+/* Initialize the host structures for LPIs and the host ITSes. */
 int gicv3_lpi_init_host_lpis(unsigned int nr_lpis);
+int gicv3_its_init(void);
 
 #else
 
@@ -67,6 +123,11 @@ static inline int gicv3_lpi_init_host_lpis(unsigned int nr_lpis)
 {
     return 0;
 }
+
+static inline int gicv3_its_init(void)
+{
+    return 0;
+}
 #endif /* CONFIG_HAS_ITS */
 
 #endif
-- 
2.9.0


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