Re: [Qemu-devel] [PATCH] piix: do not reset APIC base address (0x80) on piix4_reset.

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Dec 18, 2013 at 06:49:24PM +0200, Marcel Apfelbaum wrote:
> On Wed, 2013-12-18 at 18:33 +0200, Michael S. Tsirkin wrote:
> > On Wed, Dec 18, 2013 at 06:27:12PM +0200, Marcel Apfelbaum wrote:
> > > On Wed, 2013-12-18 at 17:22 +0200, Michael S. Tsirkin wrote:
> > > > On Wed, Dec 18, 2013 at 03:22:59PM +0100, Paolo Bonzini wrote:
> > > > > Il 11/12/2013 10:21, Gal Hammer ha scritto:
> > > > > > Fix a bug that was introduced in commit c046e8c4. QEMU fails to
> > > > > > resume from suspend mode (S3).
> > > > > > 
> > > > > > Signed-off-by: Gal Hammer <ghammer@redhat.com>
> > > > > > ---
> > > > > >  hw/acpi/piix4.c | 1 -
> > > > > >  1 file changed, 1 deletion(-)
> > > > > > 
> > > > > > diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> > > > > > index 93849c8..5c736a4 100644
> > > > > > --- a/hw/acpi/piix4.c
> > > > > > +++ b/hw/acpi/piix4.c
> > > > > > @@ -376,7 +376,6 @@ static void piix4_reset(void *opaque)
> > > > > >      pci_conf[0x5b] = 0;
> > > > > >  
> > > > > >      pci_conf[0x40] = 0x01; /* PM io base read only bit */
> > > > > > -    pci_conf[0x80] = 0;
> > > > > >  
> > > > > >      if (s->kvm_enabled) {
> > > > > >          /* Mark SMM as already inited (until KVM supports SMM). */
> > > > > 
> > > > > Note this is not the APIC base address, that one is 80h on the ISA
> > > > > bridge (function 0).  You're changing the behavior for 80h on the power
> > > > > management function, which is function 3.  The register is "PMBA—POWER
> > > > > MANAGEMENT BASE ADDRESS" and it is indeed initialized by SeaBIOS in
> > > > > piix4_pm_setup (src/fw/pciinit.c).
> > > > > 
> > > > > Michael, perhaps a part of pci_setup (same file) should run on S3 resume?
> > > > > 
> > > > > Paolo
> > > > 
> > > > Seems reasonable: either seabios or guest OS must do it, and
> > > > guest does not seem to.
> > > I was looking into this today, but it seems that we have a problem.
> > > We cannot run pci_setup() in init section:
> > > .data.varinit.seabios/src/hw/pci.h.66 is VARVERIFY32INIT but used from ['.text.runtime.seabios/src/resume.c.150', '.text.pci_setup']
> > > 
> > > Any thoughts how to get around this?
> > > Thanks,
> > > Marcel
> > 
> > We defintely don't want to do full pci enumeration.
> > Just pci_bios_init_platform or even less.
> The problem still remains, we have to use pci_bios_init_device that
> in turn uses the PCIDevices list.
> 
> Thanks,
> Marcel

It does but it does not have to.  We can use a chunk out of
pci_probe_devices to initialize struct pci_device on stack.

Basically something like the below (warning: completely untested,
sorry).

Seems much easier and more robust than building up
the list of devices in memory.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>


diff --git a/src/hw/pci.h b/src/hw/pci.h
index 9c7351d..a64f7c5 100644
--- a/src/hw/pci.h
+++ b/src/hw/pci.h
@@ -66,6 +66,7 @@ extern u64 pcimem64_start, pcimem64_end;
 extern struct hlist_head PCIDevices;
 extern int MaxPCIBus;
 int pci_probe_host(void);
+void pci_probe_device(int bdf, struct pci_device *dev);
 void pci_probe_devices(void);
 static inline u32 pci_classprog(struct pci_device *pci) {
     return (pci->class << 8) | pci->prog_if;
diff --git a/src/util.h b/src/util.h
index e6a6cb5..a8c71a8 100644
--- a/src/util.h
+++ b/src/util.h
@@ -28,6 +28,7 @@ void boot_add_cbfs(void *data, const char *desc, int prio);
 void interactive_bootmenu(void);
 void bcv_prepboot(void);
 struct pci_device;
+void pci_bios_init_device(struct pci_device *pci);
 int bootprio_find_pci_device(struct pci_device *pci);
 int bootprio_find_scsi_device(struct pci_device *pci, int target, int lun);
 int bootprio_find_ata_device(struct pci_device *pci, int chanid, int slave);
diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 34279a4..a35b58d 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -293,7 +293,7 @@ static const struct pci_device_id pci_device_tbl[] = {
     PCI_DEVICE_END,
 };
 
-static void pci_bios_init_device(struct pci_device *pci)
+void pci_bios_init_device(struct pci_device *pci)
 {
     u16 bdf = pci->bdf;
     dprintf(1, "PCI: init bdf=%02x:%02x.%x id=%04x:%04x\n"
diff --git a/src/hw/pci.c b/src/hw/pci.c
index 6c9aa81..d22804f 100644
--- a/src/hw/pci.c
+++ b/src/hw/pci.c
@@ -105,6 +105,24 @@ pci_probe_host(void)
     return 0;
 }
 
+void
+pci_probe_device(int bdf, struct pci_device *dev)
+{
+    dev->bdf = bdf;
+    u32 vendev = pci_config_readl(bdf, PCI_VENDOR_ID);
+    dev->vendor = vendev & 0xffff;
+    dev->device = vendev >> 16;
+    u32 classrev = pci_config_readl(bdf, PCI_CLASS_REVISION);
+    dev->class = classrev >> 16;
+    dev->prog_if = classrev >> 8;
+    dev->revision = classrev & 0xff;
+    dev->header_type = pci_config_readb(bdf, PCI_HEADER_TYPE);
+    u8 v = dev->header_type & 0x7f;
+    if (v == PCI_HEADER_TYPE_BRIDGE || v == PCI_HEADER_TYPE_CARDBUS) {
+        u8 secbus = pci_config_readb(bdf, PCI_SECONDARY_BUS);
+        dev->secondary_bus = secbus;
+    }
+}
 // Find all PCI devices and populate PCIDevices linked list.
 void
 pci_probe_devices(void)
@@ -145,21 +163,12 @@ pci_probe_devices(void)
             }
 
             // Populate pci_device info.
-            dev->bdf = bdf;
+            pci_probe_device(bdf, dev);
             dev->parent = parent;
             dev->rootbus = rootbus;
-            u32 vendev = pci_config_readl(bdf, PCI_VENDOR_ID);
-            dev->vendor = vendev & 0xffff;
-            dev->device = vendev >> 16;
-            u32 classrev = pci_config_readl(bdf, PCI_CLASS_REVISION);
-            dev->class = classrev >> 16;
-            dev->prog_if = classrev >> 8;
-            dev->revision = classrev & 0xff;
-            dev->header_type = pci_config_readb(bdf, PCI_HEADER_TYPE);
             u8 v = dev->header_type & 0x7f;
             if (v == PCI_HEADER_TYPE_BRIDGE || v == PCI_HEADER_TYPE_CARDBUS) {
-                u8 secbus = pci_config_readb(bdf, PCI_SECONDARY_BUS);
-                dev->secondary_bus = secbus;
+                u8 secbus = dev->secondary_bus;
                 if (secbus > bus && !busdevs[secbus])
                     busdevs[secbus] = dev;
                 if (secbus > MaxPCIBus)
diff --git a/src/resume.c b/src/resume.c
index fc2fee9..f6c8b3b 100644
--- a/src/resume.c
+++ b/src/resume.c
@@ -101,6 +101,14 @@ s3_resume(void)
     pic_setup();
     smm_setup();
 
+    int bdf;
+    foreachbdf(bdf, 0) {
+        struct pci_device pci;
+
+        pci_probe_device(bdf, &pci);
+        pci_bios_init_device(&pci);
+    }
+
     s3_resume_vga();
 
     make_bios_readonly();