# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1243329223 -3600
# Node ID ad59f1c032ec048e7abc7cbf9d0fd2576ef999e6
# Parent 916331c26dc1a312182e771c8a9c28fa0997d3c9
x86 hvm viridian: Provide dummy support for APIC assist page to satisfy Win7.
From: Tim Deegan <tim.deegan@xxxxxxxxxx>
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/hvm/viridian.c | 29 +++++++++++++++++++++++++++--
1 files changed, 27 insertions(+), 2 deletions(-)
diff -r 916331c26dc1 -r ad59f1c032ec xen/arch/x86/hvm/viridian.c
--- a/xen/arch/x86/hvm/viridian.c Tue May 26 10:05:27 2009 +0100
+++ b/xen/arch/x86/hvm/viridian.c Tue May 26 10:13:43 2009 +0100
@@ -22,6 +22,7 @@
#define VIRIDIAN_MSR_EOI 0x40000070
#define VIRIDIAN_MSR_ICR 0x40000071
#define VIRIDIAN_MSR_TPR 0x40000072
+#define VIRIDIAN_MSR_APIC_ASSIST 0x40000073
/* Viridian Hypercall Status Codes. */
#define HV_STATUS_SUCCESS 0x0000
@@ -49,14 +50,14 @@ int cpuid_viridian_leaves(unsigned int l
return 0;
leaf -= 0x40000000;
- if ( leaf > 5 )
+ if ( leaf > 6 )
return 0;
*eax = *ebx = *ecx = *edx = 0;
switch ( leaf )
{
case 0:
- *eax = 0x40000005; /* Maximum leaf */
+ *eax = 0x40000006; /* Maximum leaf */
*ebx = 0x7263694d; /* Magic numbers */
*ecx = 0x666F736F;
*edx = 0x76482074;
@@ -192,6 +193,30 @@ int wrmsr_viridian_regs(uint32_t idx, ui
vlapic_set_reg(vcpu_vlapic(current), APIC_TASKPRI, eax & 0xff);
break;
+ case VIRIDIAN_MSR_APIC_ASSIST:
+ /*
+ * We don't support the APIC assist page, and that fact is reflected in
+ * our CPUID flags. However, Windows 7 build 7000 has a bug which means
+ * that it doesn't recognise that, and tries to use the page anyway. We
+ * therefore have to fake up just enough to keep win7 happy.
+ * Fortunately, that's really easy: just setting the first four bytes
+ * in the page to zero effectively disables the page again, so that's
+ * what we do. Semantically, the first four bytes are supposed to be a
+ * flag saying whether the guest really needs to issue an EOI. Setting
+ * that flag to zero means that it must always issue one, which is what
+ * we want. Once a page has been repurposed as an APIC assist page the
+ * guest isn't allowed to set anything in it, so the flag remains zero
+ * and all is fine. The guest is allowed to clear flags in the page,
+ * but that doesn't cause us any problems.
+ */
+ if ( val & 1 ) /* APIC assist page enabled? */
+ {
+ uint32_t word = 0;
+ paddr_t page_start = val & ~1ul;
+ hvm_copy_to_guest_phys(page_start, &word, sizeof(word));
+ }
+ break;
+
default:
return 0;
}
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