[PATCH v2 26/30] xen/x86: add PCIe emulation

[Roger Pau Monne <roger.pau@citrix.com>]

Add a new MMIO handler that traps accesses to PCIe regions, as discovered by
Xen from the MCFG ACPI table. The handler used is the same as the one used
for accesses to the IO PCI configuration space.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Cc: Paul Durrant <paul.durrant@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
---
 xen/arch/x86/hvm/io.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 171 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index 779babb..088e3ec 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -46,6 +46,8 @@
 #include <xen/iocap.h>
 #include <public/hvm/ioreq.h>
 
+#include "../x86_64/mmconfig.h"
+
 /* Set permissive mode for HVM Dom0 PCI pass-through by default */
 static bool_t opt_dom0permissive = 1;
 boolean_param("dom0permissive", opt_dom0permissive);
@@ -363,7 +365,7 @@ static int hvm_pt_pci_config_access_check(struct hvm_pt_device *d,
 }
 
 static int hvm_pt_pci_read_config(struct hvm_pt_device *d, uint32_t addr,
-                                  uint32_t *data, int len)
+                                  uint32_t *data, int len, bool pcie)
 {
     uint32_t val = 0;
     struct hvm_pt_reg_group *reg_grp_entry = NULL;
@@ -377,7 +379,7 @@ static int hvm_pt_pci_read_config(struct hvm_pt_device *d, uint32_t addr,
     unsigned int func = PCI_FUNC(d->pdev->devfn);
 
     /* Sanity checks. */
-    if ( hvm_pt_pci_config_access_check(d, addr, len) )
+    if ( !pcie && hvm_pt_pci_config_access_check(d, addr, len) )
         return X86EMUL_UNHANDLEABLE;
 
     /* Find register group entry. */
@@ -468,7 +470,7 @@ static int hvm_pt_pci_read_config(struct hvm_pt_device *d, uint32_t addr,
 }
 
 static int hvm_pt_pci_write_config(struct hvm_pt_device *d, uint32_t addr,
-                                    uint32_t val, int len)
+                                    uint32_t val, int len, bool pcie)
 {
     int index = 0;
     struct hvm_pt_reg_group *reg_grp_entry = NULL;
@@ -485,7 +487,7 @@ static int hvm_pt_pci_write_config(struct hvm_pt_device *d, uint32_t addr,
     unsigned int func = PCI_FUNC(d->pdev->devfn);
 
     /* Sanity checks. */
-    if ( hvm_pt_pci_config_access_check(d, addr, len) )
+    if ( !pcie && hvm_pt_pci_config_access_check(d, addr, len) )
         return X86EMUL_UNHANDLEABLE;
 
     /* Find register group entry. */
@@ -677,7 +679,7 @@ static int hw_dpci_portio_read(const struct hvm_io_handler *handler,
     if ( dev != NULL )
     {
         reg = (currd->arch.pci_cf8 & 0xfc) | (addr & 0x3);
-        rc = hvm_pt_pci_read_config(dev, reg, &data32, size);
+        rc = hvm_pt_pci_read_config(dev, reg, &data32, size, false);
         if ( rc == X86EMUL_OKAY )
         {
             read_unlock(&currd->arch.hvm_domain.pt_lock);
@@ -722,7 +724,7 @@ static int hw_dpci_portio_write(const struct hvm_io_handler *handler,
     if ( dev != NULL )
     {
         reg = (currd->arch.pci_cf8 & 0xfc) | (addr & 0x3);
-        rc = hvm_pt_pci_write_config(dev, reg, data32, size);
+        rc = hvm_pt_pci_write_config(dev, reg, data32, size, false);
         if ( rc == X86EMUL_OKAY )
         {
             read_unlock(&currd->arch.hvm_domain.pt_lock);
@@ -1002,6 +1004,166 @@ static const struct hvm_io_ops hw_dpci_portio_ops = {
     .write = hw_dpci_portio_write
 };
 
+static struct acpi_mcfg_allocation *pcie_find_mmcfg(unsigned long addr)
+{
+    int i;
+
+    for ( i = 0; i < pci_mmcfg_config_num; i++ )
+    {
+        unsigned long start, end;
+
+        start = pci_mmcfg_config[i].address;
+        end = pci_mmcfg_config[i].address +
+              ((pci_mmcfg_config[i].end_bus_number + 1) << 20);
+        if ( addr >= start && addr < end )
+            return &pci_mmcfg_config[i];
+    }
+
+    return NULL;
+}
+
+static struct hvm_pt_device *hw_pcie_get_device(unsigned int seg,
+                                                unsigned int bus,
+                                                unsigned int slot,
+                                                unsigned int func)
+{
+    struct hvm_pt_device *dev;
+    struct domain *d = current->domain;
+
+    list_for_each_entry( dev, &d->arch.hvm_domain.pt_devices, entries )
+    {
+        if ( dev->pdev->seg != seg || dev->pdev->bus != bus ||
+             dev->pdev->devfn != PCI_DEVFN(slot, func) )
+            continue;
+
+        return dev;
+    }
+
+    return NULL;
+}
+
+static void pcie_decode_addr(unsigned long addr, unsigned int *bus,
+                             unsigned int *slot, unsigned int *func,
+                             unsigned int *reg)
+{
+
+    *bus = (addr >> 20) & 0xff;
+    *slot = (addr >> 15) & 0x1f;
+    *func = (addr >> 12) & 0x7;
+    *reg = addr & 0xfff;
+}
+
+static int pcie_range(struct vcpu *v, unsigned long addr)
+{
+
+    return pcie_find_mmcfg(addr) != NULL ? 1 : 0;
+}
+
+static int pcie_read(struct vcpu *v, unsigned long addr,
+                     unsigned int len, unsigned long *pval)
+{
+    struct acpi_mcfg_allocation *mmcfg = pcie_find_mmcfg(addr);
+    struct domain *d = v->domain;
+    unsigned int seg, bus, slot, func, reg;
+    struct hvm_pt_device *dev;
+    uint32_t val;
+    int rc;
+
+    ASSERT(mmcfg != NULL);
+
+    if ( len > 4 || len == 3 )
+        return X86EMUL_UNHANDLEABLE;
+
+    addr -= mmcfg->address;
+    seg = mmcfg->pci_segment;
+    pcie_decode_addr(addr, &bus, &slot, &func, &reg);
+
+    read_lock(&d->arch.hvm_domain.pt_lock);
+    dev = hw_pcie_get_device(seg, bus, slot, func);
+    if ( dev != NULL )
+    {
+        rc = hvm_pt_pci_read_config(dev, reg, &val, len, true);
+        if ( rc == X86EMUL_OKAY )
+        {
+            read_unlock(&d->arch.hvm_domain.pt_lock);
+            goto out;
+        }
+    }
+    read_unlock(&d->arch.hvm_domain.pt_lock);
+
+    /* Pass-through */
+    switch ( len )
+    {
+    case 1:
+        val = pci_conf_read8(seg, bus, slot, func, reg);
+        break;
+    case 2:
+        val = pci_conf_read16(seg, bus, slot, func, reg);
+        break;
+    case 4:
+        val = pci_conf_read32(seg, bus, slot, func, reg);
+        break;
+    }
+
+ out:
+    *pval = val;
+    return X86EMUL_OKAY;
+}
+
+static int pcie_write(struct vcpu *v, unsigned long addr,
+                      unsigned int len, unsigned long val)
+{
+    struct acpi_mcfg_allocation *mmcfg = pcie_find_mmcfg(addr);
+    struct domain *d = v->domain;
+    unsigned int seg, bus, slot, func, reg;
+    struct hvm_pt_device *dev;
+    int rc;
+
+    ASSERT(mmcfg != NULL);
+
+    if ( len > 4 || len == 3 )
+        return X86EMUL_UNHANDLEABLE;
+
+    addr -= mmcfg->address;
+    seg = mmcfg->pci_segment;
+    pcie_decode_addr(addr, &bus, &slot, &func, &reg);
+
+    read_lock(&d->arch.hvm_domain.pt_lock);
+    dev = hw_pcie_get_device(seg, bus, slot, func);
+    if ( dev != NULL )
+    {
+        rc = hvm_pt_pci_write_config(dev, reg, val, len, true);
+        if ( rc == X86EMUL_OKAY )
+        {
+            read_unlock(&d->arch.hvm_domain.pt_lock);
+            return rc;
+        }
+    }
+    read_unlock(&d->arch.hvm_domain.pt_lock);
+
+    /* Pass-through */
+    switch ( len )
+    {
+    case 1:
+        pci_conf_write8(seg, bus, slot, func, reg, val);
+        break;
+    case 2:
+        pci_conf_write16(seg, bus, slot, func, reg, val);
+        break;
+    case 4:
+        pci_conf_write32(seg, bus, slot, func, reg, val);
+        break;
+    }
+
+    return X86EMUL_OKAY;
+}
+
+static const struct hvm_mmio_ops pcie_mmio_ops = {
+    .check = pcie_range,
+    .read = pcie_read,
+    .write = pcie_write
+};
+
 void register_dpci_portio_handler(struct domain *d)
 {
     struct hvm_io_handler *handler = hvm_next_io_handler(d);
@@ -1011,7 +1173,10 @@ void register_dpci_portio_handler(struct domain *d)
 
     handler->type = IOREQ_TYPE_PIO;
     if ( is_hardware_domain(d) )
+    {
         handler->ops = &hw_dpci_portio_ops;
+        register_mmio_handler(d, &pcie_mmio_ops);
+    }
     else
         handler->ops = &dpci_portio_ops;
 }
-- 
2.7.4 (Apple Git-66)


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel