x86: early PV on HVM features initialization.

Initialize basic pv on hvm features adding a new Xen HVM specific
hypervisor_x86 structure.

Don't try to initialize xen-kbdfront and xen-fbfront when running on HVM
because the backends are not available.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

3 files changed, 102 insertions, 0 deletions

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 70abda7058c8..ff2546ce7178 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -45,5 +45,6 @@ extern const struct hypervisor_x86 *x86_hyper;
 /* Recognized hypervisors */
 extern const struct hypervisor_x86 x86_hyper_vmware;
 extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
+extern const struct hypervisor_x86 x86_hyper_xen_hvm;
 
 #endif
diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index dd531cc56a8f..bffd47c10fed 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -34,6 +34,7 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
 {
         &x86_hyper_vmware,
         &x86_hyper_ms_hyperv,
+        &x86_hyper_xen_hvm,
 };
 
 const struct hypervisor_x86 *x86_hyper;
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 65d8d79b46a8..09b36e9d507a 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -35,6 +35,7 @@
 #include <xen/interface/version.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/vcpu.h>
+#include <xen/interface/memory.h>
 #include <xen/features.h>
 #include <xen/page.h>
 #include <xen/hvc-console.h>
@@ -55,7 +56,9 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/reboot.h>
+#include <asm/setup.h>
 #include <asm/stackprotector.h>
+#include <asm/hypervisor.h>
 
 #include "xen-ops.h"
 #include "mmu.h"
@@ -76,6 +79,8 @@ struct shared_info xen_dummy_shared_info;
 
 void *xen_initial_gdt;
 
+RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
+
 /*
  * Point at some empty memory to start with. We map the real shared_info
  * page as soon as fixmap is up and running.
@@ -1206,3 +1211,98 @@ asmlinkage void __init xen_start_kernel(void)
         x86_64_start_reservations((char *)__pa_symbol(&boot_params));
 #endif
 }
+
+static uint32_t xen_cpuid_base(void)
+{
+        uint32_t base, eax, ebx, ecx, edx;
+        char signature[13];
+
+        for (base = 0x40000000; base < 0x40010000; base += 0x100) {
+                cpuid(base, &eax, &ebx, &ecx, &edx);
+                *(uint32_t *)(signature + 0) = ebx;
+                *(uint32_t *)(signature + 4) = ecx;
+                *(uint32_t *)(signature + 8) = edx;
+                signature[12] = 0;
+
+                if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
+                        return base;
+        }
+
+        return 0;
+}
+
+static int init_hvm_pv_info(int *major, int *minor)
+{
+        uint32_t eax, ebx, ecx, edx, pages, msr, base;
+        u64 pfn;
+
+        base = xen_cpuid_base();
+        cpuid(base + 1, &eax, &ebx, &ecx, &edx);
+
+        *major = eax >> 16;
+        *minor = eax & 0xffff;
+        printk(KERN_INFO "Xen version %d.%d.\n", *major, *minor);
+
+        cpuid(base + 2, &pages, &msr, &ecx, &edx);
+
+        pfn = __pa(hypercall_page);
+        wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+
+        xen_setup_features();
+
+        pv_info = xen_info;
+        pv_info.kernel_rpl = 0;
+
+        xen_domain_type = XEN_HVM_DOMAIN;
+
+        return 0;
+}
+
+static void __init init_shared_info(void)
+{
+        struct xen_add_to_physmap xatp;
+        struct shared_info *shared_info_page;
+
+        shared_info_page = (struct shared_info *)
+                extend_brk(PAGE_SIZE, PAGE_SIZE);
+        xatp.domid = DOMID_SELF;
+        xatp.idx = 0;
+        xatp.space = XENMAPSPACE_shared_info;
+        xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
+        if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
+                BUG();
+
+        HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
+
+        per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
+}
+
+static void __init xen_hvm_guest_init(void)
+{
+        int r;
+        int major, minor;
+
+        r = init_hvm_pv_info(&major, &minor);
+        if (r < 0)
+                return;
+
+        init_shared_info();
+}
+
+static bool __init xen_hvm_platform(void)
+{
+        if (xen_pv_domain())
+                return false;
+
+        if (!xen_cpuid_base())
+                return false;
+
+        return true;
+}
+
+const __refconst struct hypervisor_x86 x86_hyper_xen_hvm = {
+        .name                   = "Xen HVM",
+        .detect                 = xen_hvm_platform,
+        .init_platform          = xen_hvm_guest_init,
+};
+EXPORT_SYMBOL(x86_hyper_xen_hvm);