[PATCH v2 5/9] xen/pvh: Prevent PVH guests from using PIC, RTC and IOAPIC

From: Boris Ostrovsky
Date: Thu Jan 26 2017 - 15:28:41 EST


Make sure they don't use these devices since they are not emulated
for unprivileged PVH guest.

Also don't initialize hypercall page for them in init_hvm_pv_info()
since this has already been done.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
Changes in v2:
* Use cpuid_ebx() instead of cpuid()

arch/x86/xen/enlighten.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index c82fe14..6463382 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1791,20 +1791,32 @@ void __ref xen_hvm_init_shared_info(void)
static void __init init_hvm_pv_info(void)
{
int major, minor;
- uint32_t eax, ebx, ecx, edx, pages, msr, base;
- u64 pfn;
+ uint32_t eax, ebx, ecx, edx, msr, base;

base = xen_cpuid_base();
- cpuid(base + 1, &eax, &ebx, &ecx, &edx);
+ eax = cpuid_eax(base + 1);

major = eax >> 16;
minor = eax & 0xffff;
printk(KERN_INFO "Xen version %d.%d.\n", major, minor);

- cpuid(base + 2, &pages, &msr, &ecx, &edx);
+ xen_domain_type = XEN_HVM_DOMAIN;

- pfn = __pa(hypercall_page);
- wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+ /* PVH set up hypercall page earlier in xen_prepare_pvh(). */
+ if (xen_pvh_domain()) {
+ pv_info.name = "Xen PVH";
+#ifdef CONFIG_ACPI
+ /* No PIC or IOAPIC */
+ acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
+#endif
+ } else {
+ u64 pfn;
+
+ pv_info.name = "Xen HVM";
+ msr = cpuid_ebx(base + 2);
+ pfn = __pa(hypercall_page);
+ wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+ }

xen_setup_features();

@@ -1813,10 +1825,6 @@ static void __init init_hvm_pv_info(void)
this_cpu_write(xen_vcpu_id, ebx);
else
this_cpu_write(xen_vcpu_id, smp_processor_id());
-
- pv_info.name = "Xen HVM";
-
- xen_domain_type = XEN_HVM_DOMAIN;
}
#endif

@@ -1892,6 +1900,9 @@ static void __init xen_hvm_guest_init(void)

init_hvm_pv_info();

+ if (xen_pvh_domain())
+ x86_platform.legacy.rtc = 0;
+
xen_hvm_init_shared_info();

xen_panic_handler_init();
--
1.8.3.1