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[Xen-devel] [RFC PATCH v2 12/26] ARM: vGICv3: handle virtual LPI pending and property tables



Allow a guest to provide the address and size for the memory regions
it has reserved for the GICv3 pending and property tables.
We sanitise the various fields of the respective redistributor
registers and map those pages into Xen's address space to have easy
access.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/vgic-v3.c       | 202 ++++++++++++++++++++++++++++++++++++++++---
 xen/arch/arm/vgic.c          |   4 +
 xen/include/asm-arm/domain.h |   8 +-
 xen/include/asm-arm/vgic.h   |   4 +
 4 files changed, 203 insertions(+), 15 deletions(-)

diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index 0ffde74..b981d4e 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -20,12 +20,14 @@
 
 #include <xen/bitops.h>
 #include <xen/config.h>
+#include <xen/domain_page.h>
 #include <xen/lib.h>
 #include <xen/init.h>
 #include <xen/softirq.h>
 #include <xen/irq.h>
 #include <xen/sched.h>
 #include <xen/sizes.h>
+#include <xen/vmap.h>
 #include <asm/current.h>
 #include <asm/mmio.h>
 #include <asm/gic_v3_defs.h>
@@ -229,12 +231,14 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, 
mmio_info_t *info,
         goto read_reserved;
 
     case VREG64(GICR_PROPBASER):
-        /* LPI's not implemented */
-        goto read_as_zero_64;
+        if ( !vgic_reg64_check_access(dabt) ) goto bad_width;
+        *r = vgic_reg64_extract(v->domain->arch.vgic.rdist_propbase, info);
+        return 1;
 
     case VREG64(GICR_PENDBASER):
-        /* LPI's not implemented */
-        goto read_as_zero_64;
+        if ( !vgic_reg64_check_access(dabt) ) goto bad_width;
+        *r = vgic_reg64_extract(v->arch.vgic.rdist_pendbase, info);
+        return 1;
 
     case 0x0080:
         goto read_reserved;
@@ -302,11 +306,6 @@ bad_width:
     domain_crash_synchronous();
     return 0;
 
-read_as_zero_64:
-    if ( !vgic_reg64_check_access(dabt) ) goto bad_width;
-    *r = 0;
-    return 1;
-
 read_as_zero_32:
     if ( dabt.size != DABT_WORD ) goto bad_width;
     *r = 0;
@@ -331,6 +330,143 @@ read_unknown:
     return 1;
 }
 
+static uint64_t vgic_sanitise_field(uint64_t reg, uint64_t field_mask,
+                                    int field_shift,
+                                    uint64_t (*sanitise_fn)(uint64_t))
+{
+    uint64_t field = (reg & field_mask) >> field_shift;
+
+    field = sanitise_fn(field) << field_shift;
+    return (reg & ~field_mask) | field;
+}
+
+/* We want to avoid outer shareable. */
+static uint64_t vgic_sanitise_shareability(uint64_t field)
+{
+    switch (field) {
+    case GIC_BASER_OuterShareable:
+        return GIC_BASER_InnerShareable;
+    default:
+        return field;
+    }
+}
+
+/* Avoid any inner non-cacheable mapping. */
+static uint64_t vgic_sanitise_inner_cacheability(uint64_t field)
+{
+    switch (field) {
+    case GIC_BASER_CACHE_nCnB:
+    case GIC_BASER_CACHE_nC:
+        return GIC_BASER_CACHE_RaWb;
+    default:
+        return field;
+    }
+}
+
+/* Non-cacheable or same-as-inner are OK. */
+static uint64_t vgic_sanitise_outer_cacheability(uint64_t field)
+{
+    switch (field) {
+    case GIC_BASER_CACHE_SameAsInner:
+    case GIC_BASER_CACHE_nC:
+        return field;
+    default:
+        return GIC_BASER_CACHE_nC;
+    }
+}
+
+static uint64_t sanitize_propbaser(uint64_t reg)
+{
+    reg = vgic_sanitise_field(reg, GICR_PROPBASER_SHAREABILITY_MASK,
+                              GICR_PROPBASER_SHAREABILITY_SHIFT,
+                              vgic_sanitise_shareability);
+    reg = vgic_sanitise_field(reg, GICR_PROPBASER_INNER_CACHEABILITY_MASK,
+                              GICR_PROPBASER_INNER_CACHEABILITY_SHIFT,
+                              vgic_sanitise_inner_cacheability);
+    reg = vgic_sanitise_field(reg, GICR_PROPBASER_OUTER_CACHEABILITY_MASK,
+                              GICR_PROPBASER_OUTER_CACHEABILITY_SHIFT,
+                              vgic_sanitise_outer_cacheability);
+
+    reg &= ~PROPBASER_RES0_MASK;
+    reg &= ~GENMASK(51, 48);
+    return reg;
+}
+
+static uint64_t sanitize_pendbaser(uint64_t reg)
+{
+    reg = vgic_sanitise_field(reg, GICR_PENDBASER_SHAREABILITY_MASK,
+                              GICR_PENDBASER_SHAREABILITY_SHIFT,
+                              vgic_sanitise_shareability);
+    reg = vgic_sanitise_field(reg, GICR_PENDBASER_INNER_CACHEABILITY_MASK,
+                              GICR_PENDBASER_INNER_CACHEABILITY_SHIFT,
+                              vgic_sanitise_inner_cacheability);
+    reg = vgic_sanitise_field(reg, GICR_PENDBASER_OUTER_CACHEABILITY_MASK,
+                              GICR_PENDBASER_OUTER_CACHEABILITY_SHIFT,
+                              vgic_sanitise_outer_cacheability);
+
+    reg &= ~PENDBASER_RES0_MASK;
+    reg &= ~GENMASK(51, 48);
+    return reg;
+}
+
+/*
+ * Allow mapping some parts of guest memory into Xen's VA space to have easy
+ * access to it. This is to allow ITS configuration data to be held in
+ * guest memory and avoid using Xen memory for that.
+ */
+void *map_guest_pages(struct domain *d, paddr_t guest_addr, int nr_pages)
+{
+    mfn_t onepage;
+    mfn_t *pages;
+    int i;
+    void *ptr;
+
+    /* TODO: free previous mapping, change prototype? use get-put-put? */
+
+    guest_addr &= PAGE_MASK;
+
+    if ( nr_pages == 1 )
+    {
+        pages = &onepage;
+    } else
+    {
+        pages = xmalloc_array(mfn_t, nr_pages);
+        if ( !pages )
+            return NULL;
+    }
+
+    for ( i = 0; i < nr_pages; i++ )
+    {
+        get_page_from_gfn(d, (guest_addr >> PAGE_SHIFT) + i, NULL, P2M_ALLOC);
+        pages[i] = _mfn((guest_addr + i * PAGE_SIZE) >> PAGE_SHIFT);
+    }
+
+    ptr = vmap(pages, nr_pages);
+
+    if ( nr_pages > 1 )
+        xfree(pages);
+
+    return ptr;
+}
+
+void unmap_guest_pages(void *va, int nr_pages)
+{
+    paddr_t pa;
+    unsigned long i;
+
+    if ( !va )
+        return;
+
+    va = (void *)((uintptr_t)va & PAGE_MASK);
+    pa = virt_to_maddr(va);
+
+    vunmap(va);
+    for ( i = 0; i < nr_pages; i++ )
+        put_page(mfn_to_page((pa >> PAGE_SHIFT) + i));
+
+    return;
+}
+
 int vgic_lpi_get_priority(struct domain *d, uint32_t vlpi)
 {
     if ( vlpi >= d->arch.vgic.nr_lpis )
@@ -339,11 +475,20 @@ int vgic_lpi_get_priority(struct domain *d, uint32_t vlpi)
     return d->arch.vgic.proptable[vlpi - 8192] & 0xfc;
 }
 
+bool vgic_lpi_is_enabled(struct domain *d, uint32_t vlpi)
+{
+    if ( vlpi >= d->arch.vgic.nr_lpis )
+        return false;
+
+    return d->arch.vgic.proptable[vlpi - 8192] & LPI_PROP_ENABLED;
+}
+
 static int __vgic_v3_rdistr_rd_mmio_write(struct vcpu *v, mmio_info_t *info,
                                           uint32_t gicr_reg,
                                           register_t r)
 {
     struct hsr_dabt dabt = info->dabt;
+    uint64_t reg;
 
     switch ( gicr_reg )
     {
@@ -384,13 +529,42 @@ static int __vgic_v3_rdistr_rd_mmio_write(struct vcpu *v, 
mmio_info_t *info,
     case 0x0050:
         goto write_reserved;
 
-    case VREG64(GICR_PROPBASER):
-        /* LPI is not implemented */
-        goto write_ignore_64;
+    case VREG64(GICR_PROPBASER): {
+        int nr_pages;
+
+        if ( info->dabt.size < DABT_WORD ) goto bad_width;
+        if ( v->arch.vgic.flags & VGIC_V3_LPIS_ENABLED )
+            return 1;
 
+        reg = v->domain->arch.vgic.rdist_propbase;
+        if ( v->domain->arch.vgic.proptable )
+        {
+            nr_pages = BIT((reg & 0x1f) + 1) - 8192;
+            nr_pages = DIV_ROUND_UP(nr_pages, PAGE_SIZE);
+            unmap_guest_pages(v->domain->arch.vgic.proptable, nr_pages);
+        }
+        vgic_reg64_update(&reg, r, info);
+        reg = sanitize_propbaser(reg);
+        v->domain->arch.vgic.rdist_propbase = reg;
+
+        v->domain->arch.vgic.nr_lpis = BIT((reg & 0x1f) + 1) - 8192;
+        nr_pages = DIV_ROUND_UP(v->domain->arch.vgic.nr_lpis, PAGE_SIZE);
+        v->domain->arch.vgic.proptable = map_guest_pages(v->domain,
+                                                         reg & GENMASK(47, 12),
+                                                         nr_pages);
+        return 1;
+    }
     case VREG64(GICR_PENDBASER):
-        /* LPI is not implemented */
-        goto write_ignore_64;
+        if ( info->dabt.size < DABT_WORD ) goto bad_width;
+       reg = v->arch.vgic.rdist_pendbase;
+       vgic_reg64_update(&reg, r, info);
+       reg = sanitize_pendbaser(reg);
+       v->arch.vgic.rdist_pendbase = reg;
+
+        unmap_guest_pages(v->arch.vgic.pendtable, 16);
+       v->arch.vgic.pendtable = map_guest_pages(v->domain,
+                                                 reg & GENMASK(47, 12), 16);
+       return 1;
 
     case 0x0080:
         goto write_reserved;
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index f15eb3e..2a33a0e 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -497,6 +497,10 @@ struct pending_irq *lpi_to_pending(struct vcpu *v, 
unsigned int lpi,
         empty->pirq.irq = lpi;
     }
 
+    /* Update the enabled status */
+    if ( vgic_lpi_is_enabled(v->domain, lpi) )
+        set_bit(GIC_IRQ_GUEST_ENABLED, &empty->pirq.status);
+
     spin_unlock(&v->arch.vgic.pending_lpi_list_lock);
 
     return &empty->pirq;
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 02ae2cd..543d058 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -109,6 +109,9 @@ struct arch_domain
         } *rdist_regions;
         int nr_regions;                     /* Number of rdist regions */
         uint32_t rdist_stride;              /* Re-Distributor stride */
+        int nr_lpis;
+        uint64_t rdist_propbase;
+        uint8_t *proptable;
         struct list_head its_devices;       /* devices mapped to an ITS */
         spinlock_t its_devices_lock;        /* protects the its_devices list */
 #endif
@@ -254,7 +257,10 @@ struct arch_vcpu
 
         /* GICv3: redistributor base and flags for this vCPU */
         paddr_t rdist_base;
-#define VGIC_V3_RDIST_LAST  (1 << 0)        /* last vCPU of the rdist */
+#define VGIC_V3_RDIST_LAST      (1 << 0)        /* last vCPU of the rdist */
+#define VGIC_V3_LPIS_ENABLED    (1 << 1)
+        uint64_t rdist_pendbase;
+        unsigned long *pendtable;
         uint8_t flags;
         struct list_head pending_lpi_list;
         spinlock_t pending_lpi_list_lock;   /* protects the pending_lpi_list */
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index a503321..1c157d3 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -285,6 +285,9 @@ VGIC_REG_HELPERS(32, 0x3);
 
 #undef VGIC_REG_HELPERS
 
+void *map_guest_pages(struct domain *d, paddr_t guest_addr, int nr_pages);
+void unmap_guest_pages(void *va, int nr_pages);
+
 enum gic_sgi_mode;
 
 /*
@@ -312,6 +315,7 @@ extern struct vgic_irq_rank *vgic_rank_irq(struct vcpu *v, 
unsigned int irq);
 extern bool vgic_emulate(struct cpu_user_regs *regs, union hsr hsr);
 extern void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n);
 extern void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n);
+extern bool vgic_lpi_is_enabled(struct domain *d, uint32_t vlpi);
 extern int vgic_lpi_get_priority(struct domain *d, uint32_t vlpi);
 extern void register_vgic_ops(struct domain *d, const struct vgic_ops *ops);
 int vgic_v2_init(struct domain *d, int *mmio_count);
-- 
2.9.0


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