[Qemu-devel] [PATCH RFC 1 1/8] xen/pt: Use xen_host_pci_get_[byte|word] instead of dev.config

[Konrad Rzeszutek Wilk]

During init time we treat the dev.config area as a cache
of the host view. However during execution time we treat it
as guest view (by the generic PCI API). We need to sync Xen's
code to the generic PCI API view. This is the first step
by replacing all of the code that uses dev.config or
pci_get_[byte|word] to get host value to actually use the
xen_host_pci_get_[byte|word] functions.

Interestingly in 'xen_pt_ptr_reg_init' we also needed to swap
reg_field from uint32_t to uint8_t - since the access is only
for one byte not four bytes. We can split this as a seperate
patch however we would have to use a cast to thwart compiler
warnings in the meantime.

We also truncated 'flags' to 'flag' to make the code fit within
the 80 characters.

Signed-off-by: Konrad Rzeszutek Wilk <address@hidden>
---
 hw/xen/xen_pt.c             | 22 +++++++++++--
 hw/xen/xen_pt_config_init.c | 77 +++++++++++++++++++++++++++++++--------------
 2 files changed, 72 insertions(+), 27 deletions(-)

diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 1d256b9..2535352 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -738,7 +738,12 @@ static int xen_pt_initfn(PCIDevice *d)
     }
 
     /* Bind interrupt */
-    if (!s->dev.config[PCI_INTERRUPT_PIN]) {
+    if (xen_host_pci_get_byte(&s->real_device, PCI_INTERRUPT_PIN,
+                              &machine_irq /* temp scratch */)) {
+        XEN_PT_ERR(d, "Failed to read PCI_INTERRUPT_PIN! (rc:%d)\n", rc);
+        machine_irq = 0;
+    }
+    if (!machine_irq) {
         XEN_PT_LOG(d, "no pin interrupt\n");
         goto out;
     }
@@ -788,8 +793,19 @@ static int xen_pt_initfn(PCIDevice *d)
 
 out:
     if (cmd) {
-        xen_host_pci_set_word(&s->real_device, PCI_COMMAND,
-                              pci_get_word(d->config + PCI_COMMAND) | cmd);
+        uint16_t val;
+
+        rc = xen_host_pci_get_word(&s->real_device, PCI_COMMAND, &val);
+        if (rc) {
+            XEN_PT_ERR(d, "Failed to read PCI_COMMAND! (rc: %d)\n", rc);
+        }
+        else {
+            val |= cmd;
+            if (xen_host_pci_set_word(&s->real_device, PCI_COMMAND, val)) {
+                XEN_PT_ERR(d, "Failed to write PCI_COMMAND val=0x%x!(rc: 
%d)\n",
+                           val, rc);
+            }
+        }
     }
 
     memory_listener_register(&s->memory_listener, &s->dev.bus_master_as);
diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index 21d4938..e34f9f8 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -800,15 +800,21 @@ static XenPTRegInfo xen_pt_emu_reg_vendor[] = {
 static inline uint8_t get_capability_version(XenPCIPassthroughState *s,
                                              uint32_t offset)
 {
-    uint8_t flags = pci_get_byte(s->dev.config + offset + PCI_EXP_FLAGS);
-    return flags & PCI_EXP_FLAGS_VERS;
+    uint8_t flag;
+    if (xen_host_pci_get_byte(&s->real_device, offset + PCI_EXP_FLAGS, &flag)) 
{
+        return 0;
+    }
+    return flag & PCI_EXP_FLAGS_VERS;
 }
 
 static inline uint8_t get_device_type(XenPCIPassthroughState *s,
                                       uint32_t offset)
 {
-    uint8_t flags = pci_get_byte(s->dev.config + offset + PCI_EXP_FLAGS);
-    return (flags & PCI_EXP_FLAGS_TYPE) >> 4;
+    uint8_t flag;
+    if (xen_host_pci_get_byte(&s->real_device, offset + PCI_EXP_FLAGS, &flag)) 
{
+        return 0;
+    }
+    return (flag & PCI_EXP_FLAGS_TYPE) >> 4;
 }
 
 /* initialize Link Control register */
@@ -857,8 +863,14 @@ static int 
xen_pt_linkctrl2_reg_init(XenPCIPassthroughState *s,
         reg_field = XEN_PT_INVALID_REG;
     } else {
         /* set Supported Link Speed */
-        uint8_t lnkcap = pci_get_byte(s->dev.config + real_offset - reg->offset
-                                      + PCI_EXP_LNKCAP);
+        uint8_t lnkcap;
+        int rc;
+        rc = xen_host_pci_get_byte(&s->real_device,
+                                   real_offset - reg->offset + PCI_EXP_LNKCAP,
+                                   &lnkcap);
+        if (rc) {
+            return rc;
+        }
         reg_field |= PCI_EXP_LNKCAP_SLS & lnkcap;
     }
 
@@ -1039,13 +1051,15 @@ static int 
xen_pt_msgctrl_reg_init(XenPCIPassthroughState *s,
                                    XenPTRegInfo *reg, uint32_t real_offset,
                                    uint32_t *data)
 {
-    PCIDevice *d = &s->dev;
     XenPTMSI *msi = s->msi;
-    uint16_t reg_field = 0;
+    uint16_t reg_field;
+    int rc;
 
     /* use I/O device register's value as initial value */
-    reg_field = pci_get_word(d->config + real_offset);
-
+    rc = xen_host_pci_get_word(&s->real_device, real_offset, &reg_field);
+    if (rc) {
+        return rc;
+    }
     if (reg_field & PCI_MSI_FLAGS_ENABLE) {
         XEN_PT_LOG(&s->dev, "MSI already enabled, disabling it first\n");
         xen_host_pci_set_word(&s->real_device, real_offset,
@@ -1411,12 +1425,14 @@ static int 
xen_pt_msixctrl_reg_init(XenPCIPassthroughState *s,
                                     XenPTRegInfo *reg, uint32_t real_offset,
                                     uint32_t *data)
 {
-    PCIDevice *d = &s->dev;
-    uint16_t reg_field = 0;
+    uint16_t reg_field;
+    int rc;
 
     /* use I/O device register's value as initial value */
-    reg_field = pci_get_word(d->config + real_offset);
-
+    rc = xen_host_pci_get_word(&s->real_device, real_offset, &reg_field);
+    if (rc) {
+        return rc;
+    }
     if (reg_field & PCI_MSIX_FLAGS_ENABLE) {
         XEN_PT_LOG(&s->dev, "MSIX already enabled, disabling it first\n");
         xen_host_pci_set_word(&s->real_device, real_offset,
@@ -1511,8 +1527,7 @@ static int xen_pt_vendor_size_init(XenPCIPassthroughState 
*s,
                                    const XenPTRegGroupInfo *grp_reg,
                                    uint32_t base_offset, uint8_t *size)
 {
-    *size = pci_get_byte(s->dev.config + base_offset + 0x02);
-    return 0;
+    return xen_host_pci_get_byte(&s->real_device, base_offset + 0x02, size);
 }
 /* get PCI Express Capability Structure register group size */
 static int xen_pt_pcie_size_init(XenPCIPassthroughState *s,
@@ -1591,12 +1606,15 @@ static int xen_pt_msi_size_init(XenPCIPassthroughState 
*s,
                                 const XenPTRegGroupInfo *grp_reg,
                                 uint32_t base_offset, uint8_t *size)
 {
-    PCIDevice *d = &s->dev;
     uint16_t msg_ctrl = 0;
     uint8_t msi_size = 0xa;
+    int rc;
 
-    msg_ctrl = pci_get_word(d->config + (base_offset + PCI_MSI_FLAGS));
-
+    rc = xen_host_pci_get_word(&s->real_device, base_offset + PCI_MSI_FLAGS,
+                               &msg_ctrl);
+    if (rc) {
+        return rc;
+    }
     /* check if 64-bit address is capable of per-vector masking */
     if (msg_ctrl & PCI_MSI_FLAGS_64BIT) {
         msi_size += 4;
@@ -1739,11 +1757,14 @@ static int xen_pt_ptr_reg_init(XenPCIPassthroughState 
*s,
                                XenPTRegInfo *reg, uint32_t real_offset,
                                uint32_t *data)
 {
-    int i;
-    uint8_t *config = s->dev.config;
-    uint32_t reg_field = pci_get_byte(config + real_offset);
+    int i, rc;
+    uint8_t reg_field;
     uint8_t cap_id = 0;
 
+    rc = xen_host_pci_get_byte(&s->real_device, real_offset, &reg_field);
+    if (rc) {
+        return rc;
+    }
     /* find capability offset */
     while (reg_field) {
         for (i = 0; xen_pt_emu_reg_grps[i].grp_size != 0; i++) {
@@ -1752,7 +1773,11 @@ static int xen_pt_ptr_reg_init(XenPCIPassthroughState *s,
                 continue;
             }
 
-            cap_id = pci_get_byte(config + reg_field + PCI_CAP_LIST_ID);
+            rc = xen_host_pci_get_byte(&s->real_device,
+                                       reg_field + PCI_CAP_LIST_ID, &cap_id);
+            if (rc) {
+                return rc;
+            }
             if (xen_pt_emu_reg_grps[i].grp_id == cap_id) {
                 if (xen_pt_emu_reg_grps[i].grp_type == XEN_PT_GRP_TYPE_EMU) {
                     goto out;
@@ -1763,7 +1788,11 @@ static int xen_pt_ptr_reg_init(XenPCIPassthroughState *s,
         }
 
         /* next capability */
-        reg_field = pci_get_byte(config + reg_field + PCI_CAP_LIST_NEXT);
+        rc = xen_host_pci_get_byte(&s->real_device,
+                                   reg_field + PCI_CAP_LIST_NEXT, &reg_field);
+        if (rc) {
+            return rc;
+        }
     }
 
 out:
-- 
2.1.0