[Xen-devel] [PATCH v6 04/12] pvh/acpi: Handle ACPI accesses for PVH guests

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

Subsequent domctl access  VCPU map will use the same code. We create 
acpi_cpumap_access_common() routines in anticipation of these changes.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
Changes in v6:
* ACPI registers are only accessed by guest code (not by domctl), thus
  acpi_access_common() is no longer needed
* Adjusted access direction (RW) to be a boolean.
* Dropped unnecessary masking of status register

 xen/arch/x86/hvm/acpi.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++-
 xen/common/domain.c     |   1 +
 xen/common/domctl.c     |   5 +++
 xen/include/xen/sched.h |   3 ++
 4 files changed, 117 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/acpi.c b/xen/arch/x86/hvm/acpi.c
index 15a9a0e..f0a84f9 100644
--- a/xen/arch/x86/hvm/acpi.c
+++ b/xen/arch/x86/hvm/acpi.c
@@ -2,12 +2,43 @@
  *
  * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
  */
+#include <xen/acpi.h>
 #include <xen/errno.h>
 #include <xen/lib.h>
 #include <xen/sched.h>
 
 #include <public/arch-x86/xen.h>
 
+static int acpi_cpumap_access_common(struct domain *d, bool is_write,
+                                     unsigned int port,
+                                     unsigned int bytes, uint32_t *val)
+{
+    unsigned int first_byte = port - XEN_ACPI_CPU_MAP;
+
+    BUILD_BUG_ON(XEN_ACPI_CPU_MAP + XEN_ACPI_CPU_MAP_LEN
+                 > ACPI_GPE0_BLK_ADDRESS_V1);
+
+    if ( !is_write )
+    {
+        uint32_t mask = (bytes < 4) ? ~0U << (bytes * 8) : 0;
+
+        /*
+         * Clear bits that we are about to read to in case we
+         * copy fewer than @bytes.
+         */
+        *val &= mask;
+
+        if ( ((d->max_vcpus + 7) / 8) > first_byte )
+            memcpy(val, (uint8_t *)d->avail_vcpus + first_byte,
+                   min(bytes, ((d->max_vcpus + 7) / 8) - first_byte));
+    }
+    else
+        /* Guests do not write CPU map */
+        return X86EMUL_UNHANDLEABLE;
+
+    return X86EMUL_OKAY;
+}
+
 int hvm_acpi_domctl_access(struct domain *d,
                            const struct xen_domctl_acpi_access *access)
 {
@@ -17,13 +48,88 @@ int hvm_acpi_domctl_access(struct domain *d,
 static int acpi_cpumap_guest_access(int dir, unsigned int port,
                                     unsigned int bytes, uint32_t *val)
 {
-    return X86EMUL_UNHANDLEABLE;
+    return  acpi_cpumap_access_common(current->domain,
+                                      (dir == IOREQ_WRITE) ? true : false,
+                                      port, bytes, val);
 }
 
 static int acpi_guest_access(int dir, unsigned int port,
                              unsigned int bytes, uint32_t *val)
 {
-    return X86EMUL_UNHANDLEABLE;
+    struct domain *d = current->domain;
+    uint16_t *sts = NULL, *en = NULL;
+    const uint16_t *mask_en = NULL;
+    static const uint16_t pm1a_en_mask = ACPI_BITMASK_GLOBAL_LOCK_ENABLE;
+    static const uint16_t gpe0_en_mask = 1U << XEN_ACPI_GPE0_CPUHP_BIT;
+
+    ASSERT(!has_acpi_dm_ff(d));
+
+    switch ( port )
+    {
+    case ACPI_PM1A_EVT_BLK_ADDRESS_V1 ...
+        ACPI_PM1A_EVT_BLK_ADDRESS_V1 +
+        sizeof(d->arch.hvm_domain.acpi.pm1a_sts) +
+        sizeof(d->arch.hvm_domain.acpi.pm1a_en):
+
+        sts = &d->arch.hvm_domain.acpi.pm1a_sts;
+        en = &d->arch.hvm_domain.acpi.pm1a_en;
+        mask_en = &pm1a_en_mask;
+        break;
+
+    case ACPI_GPE0_BLK_ADDRESS_V1 ...
+        ACPI_GPE0_BLK_ADDRESS_V1 +
+        sizeof(d->arch.hvm_domain.acpi.gpe0_sts) +
+        sizeof(d->arch.hvm_domain.acpi.gpe0_en):
+
+        sts = &d->arch.hvm_domain.acpi.gpe0_sts;
+        en = &d->arch.hvm_domain.acpi.gpe0_en;
+        mask_en = &gpe0_en_mask;
+        break;
+
+    default:
+        return X86EMUL_UNHANDLEABLE;
+    }
+
+    if ( dir == IOREQ_READ )
+    {
+        uint32_t mask = (bytes < 4) ? ~0U << (bytes * 8) : 0;
+        uint32_t data = (((uint32_t)*en) << 16) | *sts;
+
+        data >>= 8 * (port & 3);
+        *val = (*val & mask) | (data & ~mask);
+    }
+    else
+    {
+        uint32_t v = *val;
+
+        /* Status register is write-1-to-clear */
+        switch ( port & 3 )
+        {
+        case 0:
+            *sts &= ~(v & 0xff);
+            if ( !--bytes )
+                break;
+            v >>= 8;
+            /* fallthrough */
+        case 1:
+            *sts &= ~((v & 0xff) << 8);
+            if ( !--bytes )
+                break;
+            v >>= 8;
+            /* fallthrough */
+        case 2:
+            *en = ((*en & 0xff00) | (v & 0xff)) & *mask_en;
+            if ( !--bytes )
+                break;
+            v >>= 8;
+            /* fallthrough */
+        case 3:
+            *en = (((v & 0xff) << 8) | (*en & 0xff)) & *mask_en;
+            break;
+        }
+    }
+
+    return X86EMUL_OKAY;
 }
 
 void hvm_acpi_init(struct domain *d)
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 05130e2..ca1f0ed 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -847,6 +847,7 @@ static void complete_domain_destroy(struct rcu_head *head)
     xsm_free_security_domain(d);
     free_cpumask_var(d->domain_dirty_cpumask);
     xfree(d->vcpu);
+    xfree(d->avail_vcpus);
     free_domain_struct(d);
 
     send_global_virq(VIRQ_DOM_EXC);
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index b0ee961..0a08b83 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -651,6 +651,11 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
                 goto maxvcpu_out;
         }
 
+        d->avail_vcpus = xzalloc_array(unsigned long,
+                                       BITS_TO_LONGS(d->max_vcpus));
+        if ( !d->avail_vcpus )
+            goto maxvcpu_out;
+
         ret = 0;
 
     maxvcpu_out:
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 063efe6..bee190f 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -315,6 +315,9 @@ struct domain
     unsigned int     max_vcpus;
     struct vcpu    **vcpu;
 
+    /* Bitmap of available VCPUs. */
+    unsigned long   *avail_vcpus;
+
     shared_info_t   *shared_info;     /* shared data area */
 
     spinlock_t       domain_lock;
-- 
2.7.4


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