WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH 02/10] xen: hook io_apic read/write operations

To: "H. Peter Anvin" <hpa@xxxxxxxxx>
Subject: [Xen-devel] [PATCH 02/10] xen: hook io_apic read/write operations
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Fri, 27 Feb 2009 18:14:00 -0800
Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Jeremy Fitzhardinge <jeremy@xxxxxxxx>, the arch/x86 maintainers <x86@xxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
Delivery-date: Fri, 27 Feb 2009 18:17:06 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1235787248-18184-1-git-send-email-jeremy@xxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <1235787248-18184-1-git-send-email-jeremy@xxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
In Xen, writes to the IO APIC are paravirtualized via hypercalls, so
implement the appropriate operations.

This version of the patch just hooks the io_apic read/write functions
directly, rather than introducing another layer of indirection.  The
xen_initial_domain() tests compile to 0 if CONFIG_XEN_DOM0 isn't set,
and are cheap if it is.

(An alternative would be to add io_apic_ops, and point them to the Xen
implementation as needed.  HPA deemed this extra level of indirection to
be excessive.)

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
 arch/x86/include/asm/io_apic.h |    6 ++++
 arch/x86/kernel/io_apic.c      |   32 ++++++++++++++++++++--
 arch/x86/xen/Makefile          |    2 +-
 arch/x86/xen/apic.c            |   57 ++++++++++++++++++++++++++++++++++++++++
 arch/x86/xen/enlighten.c       |    2 +
 arch/x86/xen/xen-ops.h         |    6 ++++
 6 files changed, 101 insertions(+), 4 deletions(-)
 create mode 100644 arch/x86/xen/apic.c

diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index 309d0e2..685f21b 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -177,4 +177,10 @@ static inline void ioapic_init_mappings(void)      { }
 static inline void probe_nr_irqs_gsi(void)     { }
 #endif
 
+void xen_io_apic_init(void);
+unsigned int xen_io_apic_read(unsigned apic, unsigned reg);
+void xen_io_apic_write(unsigned int apic,
+                      unsigned int reg, unsigned int value);
+
+
 #endif /* _ASM_X86_IO_APIC_H */
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index 56e51eb..6366384 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -62,6 +62,8 @@
 #include <asm/uv/uv_hub.h>
 #include <asm/uv/uv_irq.h>
 
+#include <asm/xen/hypervisor.h>
+
 #include <asm/genapic.h>
 
 #define __apicdebuginit(type) static type __init
@@ -399,14 +401,26 @@ static __attribute_const__ struct io_apic __iomem 
*io_apic_base(int idx)
 
 static inline unsigned int io_apic_read(unsigned int apic, unsigned int reg)
 {
-       struct io_apic __iomem *io_apic = io_apic_base(apic);
+       struct io_apic __iomem *io_apic;
+
+       if (xen_initial_domain())
+               return xen_io_apic_read(apic, reg);
+
+       io_apic = io_apic_base(apic);
        writel(reg, &io_apic->index);
        return readl(&io_apic->data);
 }
 
 static inline void io_apic_write(unsigned int apic, unsigned int reg, unsigned 
int value)
 {
-       struct io_apic __iomem *io_apic = io_apic_base(apic);
+       struct io_apic __iomem *io_apic;
+
+       if (xen_initial_domain()) {
+               xen_io_apic_write(apic, reg, value);
+               return;
+       }
+
+       io_apic = io_apic_base(apic);
        writel(reg, &io_apic->index);
        writel(value, &io_apic->data);
 }
@@ -419,7 +433,14 @@ static inline void io_apic_write(unsigned int apic, 
unsigned int reg, unsigned i
  */
 static inline void io_apic_modify(unsigned int apic, unsigned int reg, 
unsigned int value)
 {
-       struct io_apic __iomem *io_apic = io_apic_base(apic);
+       struct io_apic __iomem *io_apic;
+
+       if (xen_initial_domain()) {
+               xen_io_apic_write(apic, reg, value);
+               return;
+       }
+
+       io_apic = io_apic_base(apic);
 
        if (sis_apic_bug)
                writel(reg, &io_apic->index);
@@ -4113,6 +4134,11 @@ void __init ioapic_init_mappings(void)
        struct resource *ioapic_res;
        int i;
 
+       if (xen_initial_domain()) {
+               xen_io_apic_init();
+               return;
+       }
+
        ioapic_res = ioapic_setup_resources();
        for (i = 0; i < nr_ioapics; i++) {
                if (smp_found_config) {
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index c4cda96..73ecb74 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -11,4 +11,4 @@ obj-y         := enlighten.o setup.o multicalls.o mmu.o irq.o 
\
 
 obj-$(CONFIG_SMP)              += smp.o spinlock.o
 obj-$(CONFIG_XEN_DEBUG_FS)     += debugfs.o
-obj-$(CONFIG_XEN_DOM0)         += vga.o
+obj-$(CONFIG_XEN_DOM0)         += vga.o apic.o
diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
new file mode 100644
index 0000000..17736a0
--- /dev/null
+++ b/arch/x86/xen/apic.c
@@ -0,0 +1,57 @@
+#include <linux/kernel.h>
+#include <linux/threads.h>
+#include <linux/bitmap.h>
+
+#include <asm/io_apic.h>
+#include <asm/acpi.h>
+
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/physdev.h>
+
+void __init xen_io_apic_init(void)
+{
+       printk("xen apic init\n");
+       dump_stack();
+}
+
+unsigned int xen_io_apic_read(unsigned apic, unsigned reg)
+{
+       struct physdev_apic apic_op;
+       int ret;
+
+       apic_op.apic_physbase = mp_ioapics[apic].apicaddr;
+       apic_op.reg = reg;
+       ret = HYPERVISOR_physdev_op(PHYSDEVOP_apic_read, &apic_op);
+       if (ret)
+               BUG();
+       return apic_op.value;
+}
+
+
+void xen_io_apic_write(unsigned int apic, unsigned int reg, unsigned int value)
+{
+       struct physdev_apic apic_op;
+
+       apic_op.apic_physbase = mp_ioapics[apic].apicaddr;
+       apic_op.reg = reg;
+       apic_op.value = value;
+       if (HYPERVISOR_physdev_op(PHYSDEVOP_apic_write, &apic_op))
+               BUG();
+}
+
+void xen_init_apic(void)
+{
+       if (!xen_initial_domain())
+               return;
+
+#ifdef CONFIG_ACPI
+       /*
+        * Pretend ACPI found our lapic even though we've disabled it,
+        * to prevent MP tables from setting up lapics.
+        */
+       acpi_lapic = 1;
+#endif
+}
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index cf0e081..60e2de9 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -970,6 +970,8 @@ asmlinkage void __init xen_start_kernel(void)
                set_iopl.iopl = 1;
                if (HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl) == -1)
                        BUG();
+
+               xen_init_apic();
        }
 
        /* set the limit of our address space */
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index dea44b0..3337712 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -86,6 +86,12 @@ static inline void xen_init_vga(const struct 
dom0_vga_console_info *info,
 }
 #endif
 
+#ifdef CONFIG_XEN_DOM0
+void xen_init_apic(void);
+#else
+static inline void xen_init_apic(void) {}
+#endif
+
 /* Declare an asm function, along with symbols needed to make it
    inlineable */
 #define DECL_ASM(ret, name, ...)               \
-- 
1.6.0.6


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel