[Xen-devel] [XEN][RFC PATCH 03/15] hvm-pci: Handle PCI config space in Xen

[Julien Grall <julien.grall@xxxxxxxxxx>]

Add function to register a bdf with a server.
To handle cf8 -> cff we add an handler with register_portio_handle.
When Xen reveice a pio for cf8, it's store the value inside the current
vcpu until it receives a pio for cfc -> cff.
In this case, it checks if the bdf is registered and forge the ioreq
that will be forward to server later.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/x86/hvm/Makefile   |    1 +
 xen/arch/x86/hvm/pci_emul.c |  147 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 148 insertions(+), 0 deletions(-)
 create mode 100644 xen/arch/x86/hvm/pci_emul.c

diff --git a/xen/arch/x86/hvm/Makefile b/xen/arch/x86/hvm/Makefile
index eea5555..585e9c9 100644
--- a/xen/arch/x86/hvm/Makefile
+++ b/xen/arch/x86/hvm/Makefile
@@ -12,6 +12,7 @@ obj-y += irq.o
 obj-y += mtrr.o
 obj-y += nestedhvm.o
 obj-y += pmtimer.o
+obj-y += pci_emul.o
 obj-y += quirks.o
 obj-y += rtc.o
 obj-y += save.o
diff --git a/xen/arch/x86/hvm/pci_emul.c b/xen/arch/x86/hvm/pci_emul.c
new file mode 100644
index 0000000..b390e73
--- /dev/null
+++ b/xen/arch/x86/hvm/pci_emul.c
@@ -0,0 +1,147 @@
+#include <asm/hvm/support.h>
+#include <xen/hvm/pci_emul.h>
+#include <xen/pci.h>
+#include <xen/sched.h>
+#include <xen/xmalloc.h>
+
+#define PCI_DEBUGSTR "%x:%x.%x"
+#define PCI_DEBUG(bdf) ((bdf) >> 16) & 0xff, ((bdf) >> 11) & 0x1f, ((bdf) >> 
8) & 0x7
+
+static int handle_config_space(int dir, uint32_t port, uint32_t bytes,
+                               uint32_t *val)
+{
+    uint32_t pci_cf8;
+    struct pci_device_emul *pci;
+    ioreq_t *p = get_ioreq(current);
+    int rc = X86EMUL_UNHANDLEABLE;
+    struct vcpu *v = current;
+
+    spin_lock(&v->domain->arch.hvm_domain.pci_root.pci_lock);
+
+    if (port == 0xcf8)
+    {
+        rc = X86EMUL_OKAY;
+        v->arch.hvm_vcpu.pci_cf8 = *val;
+        goto end_handle;
+    }
+
+    pci_cf8 = v->arch.hvm_vcpu.pci_cf8;
+
+    /* Retrieve PCI */
+    pci = v->domain->arch.hvm_domain.pci_root.pci;
+
+    while (pci && !PCI_CMP_BDF(pci, pci_cf8))
+        pci = pci->next;
+
+    /* We just fill the ioreq, hvm_send_assist_req will send the request */
+    if (unlikely(pci == NULL))
+    {
+        *val = ~0;
+        rc = X86EMUL_OKAY;
+        goto end_handle;
+    }
+
+    p->type = IOREQ_TYPE_PCI_CONFIG;
+    p->addr = (pci_cf8 & ~3) + (p->addr & 3);
+
+    set_ioreq(v, &pci->server->ioreq, p);
+
+end_handle:
+    spin_unlock(&v->domain->arch.hvm_domain.pci_root.pci_lock);
+    return rc;
+}
+
+int hvm_register_pcidev(domid_t domid, unsigned int id, u16 bdf)
+{
+    struct domain *d;
+    struct hvm_ioreq_server *s;
+    struct pci_device_emul *x;
+    int rc = 0;
+
+    rc = rcu_lock_target_domain_by_id(domid, &d);
+
+    if (rc != 0)
+        return rc;
+
+    if (!is_hvm_domain(d))
+    {
+        rcu_unlock_domain(d);
+        return -EINVAL;
+    }
+
+    /* Search server */
+    spin_lock(&d->arch.hvm_domain.ioreq_server_lock);
+    s = d->arch.hvm_domain.ioreq_server_list;
+    while ((s != NULL) && (s->id != id))
+        s = s->next;
+
+    if (s == NULL)
+    {
+        dprintk(XENLOG_DEBUG, "Cannot find server\n");
+        rc = -ENOENT;
+        goto create_end;
+    }
+
+    spin_unlock(&d->arch.hvm_domain.ioreq_server_lock);
+
+    spin_lock(&d->arch.hvm_domain.pci_root.pci_lock);
+    x = xmalloc(struct pci_device_emul);
+
+    if (!x)
+    {
+        dprintk(XENLOG_DEBUG, "Cannot allocate pci\n");
+        rc = -ENOMEM;
+        goto create_end;
+    }
+
+    x->bdf = PCI_MASK_BDF(bdf);
+    x->server = s;
+    x->next = d->arch.hvm_domain.pci_root.pci;
+    d->arch.hvm_domain.pci_root.pci = x;
+
+create_end:
+    spin_unlock(&d->arch.hvm_domain.pci_root.pci_lock);
+    rcu_unlock_domain(d);
+
+    return rc;
+}
+
+int hvm_init_pci_emul(struct domain *d)
+{
+    struct pci_root_emul *root = &d->arch.hvm_domain.pci_root;
+
+    spin_lock_init(&root->pci_lock);
+
+    root->pci = NULL;
+
+    /* Register the config space handler */
+    register_portio_handler(d, 0xcf8, 8, handle_config_space);
+
+    return 0;
+}
+
+void hvm_destroy_pci_emul(struct domain *d)
+{
+    struct pci_root_emul *root = &d->arch.hvm_domain.pci_root;
+    struct pci_device_emul *p;
+
+    spin_lock(&root->pci_lock);
+
+    while ( (p = root->pci) != NULL )
+    {
+        root->pci = p->next;
+        xfree(p);
+    }
+
+    spin_unlock(&root->pci_lock);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
Julien Grall


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