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[Xen-devel] [RFC PATCH 02/24] ARM: GICv3: allocate LPI pending and property table



The ARM GICv3 ITS provides a new kind of interrupt called LPIs.
The pending bits and the configuration data (priority, enable bits) for
those LPIs are stored in tables in normal memory, which software has to
provide to the hardware.
Allocate the required memory, initialize it and hand it over to each
ITS. We limit the number of LPIs we use with a compile time constant to
avoid wasting memory.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/Kconfig              |  6 ++++
 xen/arch/arm/efi/efi-boot.h       |  1 -
 xen/arch/arm/gic-its.c            | 76 +++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/gic-v3.c             | 27 ++++++++++++++
 xen/include/asm-arm/cache.h       |  4 +++
 xen/include/asm-arm/gic-its.h     | 22 +++++++++++-
 xen/include/asm-arm/gic_v3_defs.h | 48 ++++++++++++++++++++++++-
 7 files changed, 181 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
index 9fe3b8e..66e2bb8 100644
--- a/xen/arch/arm/Kconfig
+++ b/xen/arch/arm/Kconfig
@@ -50,6 +50,12 @@ config HAS_ITS
         depends on ARM_64
         depends on HAS_GICV3
 
+config HOST_LPI_BITS
+        depends on HAS_ITS
+        int "Maximum bits for GICv3 host LPIs (14-32)"
+        range 14 32
+        default "20"
+
 config ALTERNATIVE
        bool
 
diff --git a/xen/arch/arm/efi/efi-boot.h b/xen/arch/arm/efi/efi-boot.h
index 045d6ce..dc64aec 100644
--- a/xen/arch/arm/efi/efi-boot.h
+++ b/xen/arch/arm/efi/efi-boot.h
@@ -10,7 +10,6 @@
 #include "efi-dom0.h"
 
 void noreturn efi_xen_start(void *fdt_ptr, uint32_t fdt_size);
-void __flush_dcache_area(const void *vaddr, unsigned long size);
 
 #define DEVICE_TREE_GUID \
 {0xb1b621d5, 0xf19c, 0x41a5, {0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0}}
diff --git a/xen/arch/arm/gic-its.c b/xen/arch/arm/gic-its.c
index 0f42a77..b52dff3 100644
--- a/xen/arch/arm/gic-its.c
+++ b/xen/arch/arm/gic-its.c
@@ -20,10 +20,86 @@
 #include <xen/lib.h>
 #include <xen/device_tree.h>
 #include <xen/libfdt/libfdt.h>
+#include <asm/p2m.h>
 #include <asm/gic.h>
 #include <asm/gic_v3_defs.h>
 #include <asm/gic-its.h>
 
+/* Global state */
+static struct {
+    uint8_t *lpi_property;
+    int host_lpi_bits;
+} lpi_data;
+
+/* Pending table for each redistributor */
+static DEFINE_PER_CPU(void *, pending_table);
+
+#define MAX_HOST_LPI_BITS                                                \
+        min_t(unsigned int, lpi_data.host_lpi_bits, CONFIG_HOST_LPI_BITS)
+#define MAX_HOST_LPIS   (BIT(MAX_HOST_LPI_BITS) - 8192)
+
+uint64_t gicv3_lpi_allocate_pendtable(void)
+{
+    uint64_t reg, attr;
+    void *pendtable;
+
+    attr  = GIC_BASER_CACHE_RaWaWb << GICR_PENDBASER_INNER_CACHEABILITY_SHIFT;
+    attr |= GIC_BASER_CACHE_SameAsInner << 
GICR_PENDBASER_OUTER_CACHEABILITY_SHIFT;
+    attr |= GIC_BASER_InnerShareable << GICR_PENDBASER_SHAREABILITY_SHIFT;
+
+    /*
+     * The pending table holds one bit per LPI, so we need three bits less
+     * than the number of LPI_BITs. But the alignment requirement from the
+     * ITS is 64K, so make order at least 16 (-12).
+     */
+    pendtable = alloc_xenheap_pages(MAX(lpi_data.host_lpi_bits - 3, 16) - 12, 
0);
+    if ( !pendtable )
+        return 0;
+
+    memset(pendtable, 0, BIT(lpi_data.host_lpi_bits - 3));
+    this_cpu(pending_table) = pendtable;
+
+    reg  = attr | GICR_PENDBASER_PTZ;
+    reg |= virt_to_maddr(pendtable) & GENMASK(51, 16);
+
+    return reg;
+}
+
+uint64_t gicv3_lpi_get_proptable()
+{
+    uint64_t attr;
+    static uint64_t reg = 0;
+
+    /* The property table is shared across all redistributors. */
+    if ( reg )
+        return reg;
+
+    attr  = GIC_BASER_CACHE_RaWaWb << GICR_PENDBASER_INNER_CACHEABILITY_SHIFT;
+    attr |= GIC_BASER_CACHE_SameAsInner << 
GICR_PENDBASER_OUTER_CACHEABILITY_SHIFT;
+    attr |= GIC_BASER_InnerShareable << GICR_PENDBASER_SHAREABILITY_SHIFT;
+
+    lpi_data.lpi_property = alloc_xenheap_pages(MAX_HOST_LPI_BITS - 12, 0);
+    if ( !lpi_data.lpi_property )
+        return 0;
+
+    memset(lpi_data.lpi_property, GIC_PRI_IRQ | LPI_PROP_RES1, MAX_HOST_LPIS);
+    __flush_dcache_area(lpi_data.lpi_property, MAX_HOST_LPIS);
+
+    reg  = attr | ((MAX_HOST_LPI_BITS - 1) << 0);
+    reg |= virt_to_maddr(lpi_data.lpi_property) & GENMASK(51, 12);
+
+    return reg;
+}
+
+int gicv3_lpi_init_host_lpis(int lpi_bits)
+{
+    lpi_data.host_lpi_bits = lpi_bits;
+
+    printk("GICv3: using at most %ld LPIs on the host.\n", MAX_HOST_LPIS);
+
+    return 0;
+}
+
 void gicv3_its_dt_init(const struct dt_device_node *node)
 {
     const struct dt_device_node *its = NULL;
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 238da84..2534aa5 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -546,6 +546,9 @@ static void __init gicv3_dist_init(void)
     type = readl_relaxed(GICD + GICD_TYPER);
     nr_lines = 32 * ((type & GICD_TYPE_LINES) + 1);
 
+    if ( type & GICD_TYPE_LPIS )
+        gicv3_lpi_init_host_lpis(((type >> GICD_TYPE_ID_BITS_SHIFT) & 0x1f) + 
1);
+
     printk("GICv3: %d lines, (IID %8.8x).\n",
            nr_lines, readl_relaxed(GICD + GICD_IIDR));
 
@@ -615,6 +618,26 @@ static int gicv3_enable_redist(void)
 
     return 0;
 }
+static void gicv3_rdist_init_lpis(void __iomem * rdist_base)
+{
+    uint32_t reg;
+    uint64_t table_reg;
+
+    if ( list_empty(&host_its_list) )
+        return;
+
+    /* Make sure LPIs are disabled before setting up the BASERs. */
+    reg = readl_relaxed(rdist_base + GICR_CTLR);
+    writel_relaxed(reg & ~GICR_CTLR_ENABLE_LPIS, rdist_base + GICR_CTLR);
+
+    table_reg = gicv3_lpi_allocate_pendtable();
+    if ( table_reg )
+        writeq_relaxed(table_reg, rdist_base + GICR_PENDBASER);
+
+    table_reg = gicv3_lpi_get_proptable();
+    if ( table_reg )
+        writeq_relaxed(table_reg, rdist_base + GICR_PROPBASER);
+}
 
 static int __init gicv3_populate_rdist(void)
 {
@@ -658,6 +681,10 @@ static int __init gicv3_populate_rdist(void)
             if ( (typer >> 32) == aff )
             {
                 this_cpu(rbase) = ptr;
+
+                if ( typer & GICR_TYPER_PLPIS )
+                    gicv3_rdist_init_lpis(ptr);
+
                 printk("GICv3: CPU%d: Found redistributor in region %d @%p\n",
                         smp_processor_id(), i, ptr);
                 return 0;
diff --git a/xen/include/asm-arm/cache.h b/xen/include/asm-arm/cache.h
index 2de6564..af96eee 100644
--- a/xen/include/asm-arm/cache.h
+++ b/xen/include/asm-arm/cache.h
@@ -7,6 +7,10 @@
 #define L1_CACHE_SHIFT  (CONFIG_ARM_L1_CACHE_SHIFT)
 #define L1_CACHE_BYTES  (1 << L1_CACHE_SHIFT)
 
+#ifndef __ASSEMBLY__
+void __flush_dcache_area(const void *vaddr, unsigned long size);
+#endif
+
 #define __read_mostly __section(".data.read_mostly")
 
 #endif
diff --git a/xen/include/asm-arm/gic-its.h b/xen/include/asm-arm/gic-its.h
index 2f5c51c..48c6c78 100644
--- a/xen/include/asm-arm/gic-its.h
+++ b/xen/include/asm-arm/gic-its.h
@@ -36,12 +36,32 @@ extern struct list_head host_its_list;
 /* Parse the host DT and pick up all host ITSes. */
 void gicv3_its_dt_init(const struct dt_device_node *node);
 
+/* Allocate and initialize tables for each host redistributor.
+ * Returns the respective {PROP,PEND}BASER register value.
+ */
+uint64_t gicv3_lpi_get_proptable(void);
+uint64_t gicv3_lpi_allocate_pendtable(void);
+
+/* Initialize the host structures for LPIs. */
+int gicv3_lpi_init_host_lpis(int nr_lpis);
+
 #else
 
 static inline void gicv3_its_dt_init(const struct dt_device_node *node)
 {
 }
-
+static inline uint64_t gicv3_lpi_get_proptable(void)
+{
+    return 0;
+}
+static inline uint64_t gicv3_lpi_allocate_pendtable(void)
+{
+    return 0;
+}
+static inline int gicv3_lpi_init_host_lpis(int nr_lpis)
+{
+    return 0;
+}
 #endif /* CONFIG_HAS_ITS */
 
 #endif /* __ASSEMBLY__ */
diff --git a/xen/include/asm-arm/gic_v3_defs.h 
b/xen/include/asm-arm/gic_v3_defs.h
index 6bd25a5..da5fb77 100644
--- a/xen/include/asm-arm/gic_v3_defs.h
+++ b/xen/include/asm-arm/gic_v3_defs.h
@@ -44,7 +44,8 @@
 #define GICC_SRE_EL2_ENEL1           (1UL << 3)
 
 /* Additional bits in GICD_TYPER defined by GICv3 */
-#define GICD_TYPE_ID_BITS_SHIFT 19
+#define GICD_TYPE_ID_BITS_SHIFT      19
+#define GICD_TYPE_LPIS               (1U << 17)
 
 #define GICD_CTLR_RWP                (1UL << 31)
 #define GICD_CTLR_ARE_NS             (1U << 4)
@@ -95,12 +96,57 @@
 #define GICR_IGRPMODR0               (0x0D00)
 #define GICR_NSACR                   (0x0E00)
 
+#define GICR_CTLR_ENABLE_LPIS        (1U << 0)
 #define GICR_TYPER_PLPIS             (1U << 0)
 #define GICR_TYPER_VLPIS             (1U << 1)
 #define GICR_TYPER_LAST              (1U << 4)
 
+#define GIC_BASER_CACHE_nCnB         0ULL
+#define GIC_BASER_CACHE_SameAsInner  0ULL
+#define GIC_BASER_CACHE_nC           1ULL
+#define GIC_BASER_CACHE_RaWt         2ULL
+#define GIC_BASER_CACHE_RaWb         3ULL
+#define GIC_BASER_CACHE_WaWt         4ULL
+#define GIC_BASER_CACHE_WaWb         5ULL
+#define GIC_BASER_CACHE_RaWaWt       6ULL
+#define GIC_BASER_CACHE_RaWaWb       7ULL
+#define GIC_BASER_CACHE_MASK         7ULL
+#define GIC_BASER_NonShareable       0ULL
+#define GIC_BASER_InnerShareable     1ULL
+#define GIC_BASER_OuterShareable     2ULL
+
+#define GICR_PROPBASER_SHAREABILITY_SHIFT               10
+#define GICR_PROPBASER_INNER_CACHEABILITY_SHIFT         7
+#define GICR_PROPBASER_OUTER_CACHEABILITY_SHIFT         56
+#define GICR_PROPBASER_SHAREABILITY_MASK                     \
+        (3UL << GICR_PROPBASER_SHAREABILITY_SHIFT)
+#define GICR_PROPBASER_INNER_CACHEABILITY_MASK               \
+        (7UL << GICR_PROPBASER_INNER_CACHEABILITY_SHIFT)
+#define GICR_PROPBASER_OUTER_CACHEABILITY_MASK               \
+        (7UL << GICR_PROPBASER_OUTER_CACHEABILITY_SHIFT)
+#define PROPBASER_RES0_MASK                                  \
+        (GENMASK(63, 59) | GENMASK(55, 52) | GENMASK(6, 5))
+
+#define GICR_PENDBASER_SHAREABILITY_SHIFT               10
+#define GICR_PENDBASER_INNER_CACHEABILITY_SHIFT         7
+#define GICR_PENDBASER_OUTER_CACHEABILITY_SHIFT         56
+#define GICR_PENDBASER_SHAREABILITY_MASK                     \
+       (3UL << GICR_PENDBASER_SHAREABILITY_SHIFT)
+#define GICR_PENDBASER_INNER_CACHEABILITY_MASK               \
+       (7UL << GICR_PENDBASER_INNER_CACHEABILITY_SHIFT)
+#define GICR_PENDBASER_OUTER_CACHEABILITY_MASK               \
+        (7UL << GICR_PENDBASER_OUTER_CACHEABILITY_SHIFT)
+#define GICR_PENDBASER_PTZ                              BIT(62)
+#define PENDBASER_RES0_MASK                                  \
+        (BIT(63) | GENMASK(61, 59) | GENMASK(55, 52) |       \
+         GENMASK(15, 12) | GENMASK(6, 0))
+
 #define DEFAULT_PMR_VALUE            0xff
 
+#define LPI_PROP_DEFAULT_PRIO        0xa0
+#define LPI_PROP_RES1                (1 << 1)
+#define LPI_PROP_ENABLED             (1 << 0)
+
 #define GICH_VMCR_EOI                (1 << 9)
 #define GICH_VMCR_VENG1              (1 << 1)
 
-- 
2.9.0


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