xen: mask XSAVE from cpuid

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / xen / enlighten.c

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 82cd39a6cbd3a116b83c5ce1cf30cae0214991f6..da33e0c5870d94b9c8828e1ca0d511ac7c43deee 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -168,21 +168,23 @@ static void __init xen_banner(void)
               xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
 }
 
+static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
+static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
+
 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
                      unsigned int *cx, unsigned int *dx)
 {
+       unsigned maskecx = ~0;
        unsigned maskedx = ~0;
 
        /*
         * Mask out inconvenient features, to try and disable as many
         * unsupported kernel subsystems as possible.
         */
-       if (*ax == 1)
-               maskedx = ~((1 << X86_FEATURE_APIC) |  /* disable APIC */
-                           (1 << X86_FEATURE_ACPI) |  /* disable ACPI */
-                           (1 << X86_FEATURE_MCE)  |  /* disable MCE */
-                           (1 << X86_FEATURE_MCA)  |  /* disable MCA */
-                           (1 << X86_FEATURE_ACC));   /* thermal monitoring */
+       if (*ax == 1) {
+               maskecx = cpuid_leaf1_ecx_mask;
+               maskedx = cpuid_leaf1_edx_mask;
+       }
 
        asm(XEN_EMULATE_PREFIX "cpuid"
                : "=a" (*ax),
@@ -190,9 +192,43 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
                  "=c" (*cx),
                  "=d" (*dx)
                : "0" (*ax), "2" (*cx));
+
+       *cx &= maskecx;
        *dx &= maskedx;
 }
 
+static __init void xen_init_cpuid_mask(void)
+{
+       unsigned int ax, bx, cx, dx;
+
+       cpuid_leaf1_edx_mask =
+               ~((1 << X86_FEATURE_MCE)  |  /* disable MCE */
+                 (1 << X86_FEATURE_MCA)  |  /* disable MCA */
+                 (1 << X86_FEATURE_ACC));   /* thermal monitoring */
+
+       if (!xen_initial_domain())
+               cpuid_leaf1_edx_mask &=
+                       ~((1 << X86_FEATURE_APIC) |  /* disable local APIC */
+                         (1 << X86_FEATURE_ACPI));  /* disable ACPI */
+
+       ax = 1;
+       xen_cpuid(&ax, &bx, &cx, &dx);
+
+       /* cpuid claims we support xsave; try enabling it to see what happens */
+       if (cx & (1 << (X86_FEATURE_XSAVE % 32))) {
+               unsigned long cr4;
+
+               set_in_cr4(X86_CR4_OSXSAVE);
+               
+               cr4 = read_cr4();
+
+               if ((cr4 & X86_CR4_OSXSAVE) == 0)
+                       cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32));
+
+               clear_in_cr4(X86_CR4_OSXSAVE);
+       }
+}
+
 static void xen_set_debugreg(int reg, unsigned long val)
 {
        HYPERVISOR_set_debugreg(reg, val);
@@ -203,10 +239,10 @@ static unsigned long xen_get_debugreg(int reg)
        return HYPERVISOR_get_debugreg(reg);
 }
 
-void xen_leave_lazy(void)
+static void xen_end_context_switch(struct task_struct *next)
 {
-       paravirt_leave_lazy(paravirt_get_lazy_mode());
        xen_mc_flush();
+       paravirt_end_context_switch(next);
 }
 
 static unsigned long xen_store_tr(void)
@@ -284,12 +320,11 @@ static void xen_set_ldt(const void *addr, unsigned entries)
 
 static void xen_load_gdt(const struct desc_ptr *dtr)
 {
-       unsigned long *frames;
        unsigned long va = dtr->address;
        unsigned int size = dtr->size + 1;
        unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+       unsigned long frames[pages];
        int f;
-       struct multicall_space mcs;
 
        /* A GDT can be up to 64k in size, which corresponds to 8192
           8-byte entries, or 16 4k pages.. */
@@ -297,19 +332,26 @@ static void xen_load_gdt(const struct desc_ptr *dtr)
        BUG_ON(size > 65536);
        BUG_ON(va & ~PAGE_MASK);
 
-       mcs = xen_mc_entry(sizeof(*frames) * pages);
-       frames = mcs.args;
-
        for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
-               frames[f] = arbitrary_virt_to_mfn((void *)va);
+               int level;
+               pte_t *ptep = lookup_address(va, &level);
+               unsigned long pfn, mfn;
+               void *virt;
+
+               BUG_ON(ptep == NULL);
+
+               pfn = pte_pfn(*ptep);
+               mfn = pfn_to_mfn(pfn);
+               virt = __va(PFN_PHYS(pfn));
+
+               frames[f] = mfn;
 
                make_lowmem_page_readonly((void *)va);
-               make_lowmem_page_readonly(mfn_to_virt(frames[f]));
+               make_lowmem_page_readonly(virt);
        }
 
-       MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct));
-
-       xen_mc_issue(PARAVIRT_LAZY_CPU);
+       if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
+               BUG();
 }
 
 static void load_TLS_descriptor(struct thread_struct *t,
@@ -817,10 +859,8 @@ static const struct pv_cpu_ops xen_cpu_ops __initdata = {
        /* Xen takes care of %gs when switching to usermode for us */
        .swapgs = paravirt_nop,
 
-       .lazy_mode = {
-               .enter = paravirt_enter_lazy_cpu,
-               .leave = xen_leave_lazy,
-       },
+       .start_context_switch = paravirt_start_context_switch,
+       .end_context_switch = xen_end_context_switch,
 };
 
 static const struct pv_apic_ops xen_apic_ops __initdata = {
@@ -897,6 +937,8 @@ asmlinkage void __init xen_start_kernel(void)
 
        xen_init_irq_ops();
 
+       xen_init_cpuid_mask();
+
 #ifdef CONFIG_X86_LOCAL_APIC
        /*
         * set up the basic apic ops.