#include <xen/config.h>
#include <xen/init.h>
#include <xen/kernel.h>
#include <xen/string.h>
#include <xen/bitops.h>
#include <xen/smp.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/uaccess.h>
#include <asm/mpspec.h>
#include <asm/apic.h>
#include <asm/i387.h>
#include <mach_apic.h>
#include <asm/hvm/support.h>
#include <asm/setup.h>

#include "cpu.h"

#define select_idle_routine(x) ((void)0)

static bool __init probe_intel_cpuid_faulting(void)
{
	uint64_t x;

	if (rdmsr_safe(MSR_INTEL_PLATFORM_INFO, x) ||
	    !(x & MSR_PLATFORM_INFO_CPUID_FAULTING))
		return 0;

	expected_levelling_cap |= LCAP_faulting;
	levelling_caps |=  LCAP_faulting;
	__set_bit(X86_FEATURE_CPUID_FAULTING, boot_cpu_data.x86_capability);
	return 1;
}

DEFINE_PER_CPU(bool, cpuid_faulting_enabled);

static void set_cpuid_faulting(bool enable)
{
	bool *this_enabled = &this_cpu(cpuid_faulting_enabled);
	uint32_t hi, lo;

	ASSERT(cpu_has_cpuid_faulting);

	if (*this_enabled == enable)
		return;

	rdmsr(MSR_INTEL_MISC_FEATURES_ENABLES, lo, hi);
	lo &= ~MSR_MISC_FEATURES_CPUID_FAULTING;
	if (enable)
		lo |= MSR_MISC_FEATURES_CPUID_FAULTING;
	wrmsr(MSR_INTEL_MISC_FEATURES_ENABLES, lo, hi);

	*this_enabled = enable;
}

/*
 * Set caps in expected_levelling_cap, probe a specific masking MSR, and set
 * caps in levelling_caps if it is found, or clobber the MSR index if missing.
 * If preset, reads the default value into msr_val.
 */
static uint64_t __init _probe_mask_msr(unsigned int *msr, uint64_t caps)
{
	uint64_t val = 0;

	expected_levelling_cap |= caps;

	if (rdmsr_safe(*msr, val) || wrmsr_safe(*msr, val))
		*msr = 0;
	else
		levelling_caps |= caps;

	return val;
}

/* Indices of the masking MSRs, or 0 if unavailable. */
static unsigned int __read_mostly msr_basic, __read_mostly msr_ext,
	__read_mostly msr_xsave;

/*
 * Probe for the existance of the expected masking MSRs.  They might easily
 * not be available if Xen is running virtualised.
 */
static void __init probe_masking_msrs(void)
{
	const struct cpuinfo_x86 *c = &boot_cpu_data;
	unsigned int exp_msr_basic, exp_msr_ext, exp_msr_xsave;

	/* Only family 6 supports this feature. */
	if (c->x86 != 6)
		return;

	switch (c->x86_model) {
	case 0x17: /* Yorkfield, Wolfdale, Penryn, Harpertown(DP) */
	case 0x1d: /* Dunnington(MP) */
		msr_basic = MSR_INTEL_MASK_V1_CPUID1;
		break;

	case 0x1a: /* Bloomfield, Nehalem-EP(Gainestown) */
	case 0x1e: /* Clarksfield, Lynnfield, Jasper Forest */
	case 0x1f: /* Something Nehalem-based - perhaps Auburndale/Havendale? */
	case 0x25: /* Arrandale, Clarksdale */
	case 0x2c: /* Gulftown, Westmere-EP */
	case 0x2e: /* Nehalem-EX(Beckton) */
	case 0x2f: /* Westmere-EX */
		msr_basic = MSR_INTEL_MASK_V2_CPUID1;
		msr_ext   = MSR_INTEL_MASK_V2_CPUID80000001;
		break;

	case 0x2a: /* SandyBridge */
	case 0x2d: /* SandyBridge-E, SandyBridge-EN, SandyBridge-EP */
		msr_basic = MSR_INTEL_MASK_V3_CPUID1;
		msr_ext   = MSR_INTEL_MASK_V3_CPUID80000001;
		msr_xsave = MSR_INTEL_MASK_V3_CPUIDD_01;
		break;
	}

	exp_msr_basic = msr_basic;
	exp_msr_ext   = msr_ext;
	exp_msr_xsave = msr_xsave;

	if (msr_basic)
		cpuidmask_defaults._1cd = _probe_mask_msr(&msr_basic, LCAP_1cd);

	if (msr_ext)
		cpuidmask_defaults.e1cd = _probe_mask_msr(&msr_ext, LCAP_e1cd);

	if (msr_xsave)
		cpuidmask_defaults.Da1 = _probe_mask_msr(&msr_xsave, LCAP_Da1);

	/*
	 * Don't bother warning about a mismatch if virtualised.  These MSRs
	 * are not architectural and almost never virtualised.
	 */
	if ((expected_levelling_cap == levelling_caps) ||
	    cpu_has_hypervisor)
		return;

	printk(XENLOG_WARNING "Mismatch between expected (%#x) "
	       "and real (%#x) levelling caps: missing %#x\n",
	       expected_levelling_cap, levelling_caps,
	       (expected_levelling_cap ^ levelling_caps) & levelling_caps);
	printk(XENLOG_WARNING "Fam %#x, model %#x expected (%#x/%#x/%#x), "
	       "got (%#x/%#x/%#x)\n", c->x86, c->x86_model,
	       exp_msr_basic, exp_msr_ext, exp_msr_xsave,
	       msr_basic, msr_ext, msr_xsave);
	printk(XENLOG_WARNING
	       "If not running virtualised, please report a bug\n");
}

/*
 * Context switch levelling state to the next domain.  A parameter of NULL is
 * used to context switch to the default host state (by the cpu bringup-code,
 * crash path, etc).
 */
static void intel_ctxt_switch_levelling(const struct vcpu *next)
{
	struct cpuidmasks *these_masks = &this_cpu(cpuidmasks);
	const struct domain *nextd = next ? next->domain : NULL;
	const struct cpuidmasks *masks;

	if (cpu_has_cpuid_faulting) {
		/*
		 * We *should* be enabling faulting for the control domain.
		 *
		 * Unfortunately, the domain builder (having only ever been a
		 * PV guest) expects to be able to see host cpuid state in a
		 * native CPUID instruction, to correctly build a CPUID policy
		 * for HVM guests (notably the xstate leaves).
		 *
		 * This logic is fundimentally broken for HVM toolstack
		 * domains, and faulting causes PV guests to behave like HVM
		 * guests from their point of view.
		 *
		 * Future development plans will move responsibility for
		 * generating the maximum full cpuid policy into Xen, at which
		 * this problem will disappear.
		 */
		set_cpuid_faulting(nextd && is_pv_domain(nextd) &&
				   !is_control_domain(nextd));
		return;
	}

	masks = (nextd && is_pv_domain(nextd) && nextd->arch.pv_domain.cpuidmasks)
		? nextd->arch.pv_domain.cpuidmasks : &cpuidmask_defaults;

        if (msr_basic) {
		uint64_t val = masks->_1cd;

		/*
		 * OSXSAVE defaults to 1, which causes fast-forwarding of
		 * Xen's real setting.  Clobber it if disabled by the guest
		 * kernel.
		 */
		if (next && is_pv_vcpu(next) && !is_idle_vcpu(next) &&
		    !(next->arch.pv_vcpu.ctrlreg[4] & X86_CR4_OSXSAVE))
			val &= ~(uint64_t)cpufeat_mask(X86_FEATURE_OSXSAVE);

		if (unlikely(these_masks->_1cd != val)) {
			wrmsrl(msr_basic, val);
			these_masks->_1cd = val;
		}
        }

#define LAZY(msr, field)						\
	({								\
		if (unlikely(these_masks->field != masks->field) &&	\
		    (msr))						\
		{							\
			wrmsrl((msr), masks->field);			\
			these_masks->field = masks->field;		\
		}							\
	})

	LAZY(msr_ext,   e1cd);
	LAZY(msr_xsave, Da1);

#undef LAZY
}

/*
 * opt_cpuid_mask_ecx/edx: cpuid.1[ecx, edx] feature mask.
 * For example, E8400[Intel Core 2 Duo Processor series] ecx = 0x0008E3FD,
 * edx = 0xBFEBFBFF when executing CPUID.EAX = 1 normally. If you want to
 * 'rev down' to E8400, you can set these values in these Xen boot parameters.
 */
static void __init noinline intel_init_levelling(void)
{
	if (!probe_intel_cpuid_faulting())
		probe_masking_msrs();

	if (msr_basic) {
		uint32_t ecx, edx, tmp;

		cpuid(0x00000001, &tmp, &tmp, &ecx, &edx);

		ecx &= opt_cpuid_mask_ecx;
		edx &= opt_cpuid_mask_edx;

		/* Fast-forward bits - Must be set. */
		if (ecx & cpufeat_mask(X86_FEATURE_XSAVE))
			ecx |= cpufeat_mask(X86_FEATURE_OSXSAVE);
		edx |= cpufeat_mask(X86_FEATURE_APIC);

		cpuidmask_defaults._1cd &= ((u64)edx << 32) | ecx;
	}

	if (msr_ext) {
		uint32_t ecx, edx, tmp;

		cpuid(0x80000001, &tmp, &tmp, &ecx, &edx);

		ecx &= opt_cpuid_mask_ext_ecx;
		edx &= opt_cpuid_mask_ext_edx;

		cpuidmask_defaults.e1cd &= ((u64)edx << 32) | ecx;
	}

	if (msr_xsave) {
		uint32_t eax, tmp;

		cpuid_count(0x0000000d, 1, &eax, &tmp, &tmp, &tmp);

		eax &= opt_cpuid_mask_xsave_eax;

		cpuidmask_defaults.Da1 &= (~0ULL << 32) | eax;
	}

	if (opt_cpu_info) {
		printk(XENLOG_INFO "Levelling caps: %#x\n", levelling_caps);

		if (!cpu_has_cpuid_faulting)
			printk(XENLOG_INFO
			       "MSR defaults: 1d 0x%08x, 1c 0x%08x, e1d 0x%08x, "
			       "e1c 0x%08x, Da1 0x%08x\n",
			       (uint32_t)(cpuidmask_defaults._1cd >> 32),
			       (uint32_t)cpuidmask_defaults._1cd,
			       (uint32_t)(cpuidmask_defaults.e1cd >> 32),
			       (uint32_t)cpuidmask_defaults.e1cd,
			       (uint32_t)cpuidmask_defaults.Da1);
	}

	if (levelling_caps)
		ctxt_switch_levelling = intel_ctxt_switch_levelling;
}

static void early_init_intel(struct cpuinfo_x86 *c)
{
	/* Netburst reports 64 bytes clflush size, but does IO in 128 bytes */
	if (c->x86 == 15 && c->x86_cache_alignment == 64)
		c->x86_cache_alignment = 128;

	/* Unmask CPUID levels and NX if masked: */
	if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
		u64 misc_enable, disable;

		rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);

		disable = misc_enable & (MSR_IA32_MISC_ENABLE_LIMIT_CPUID |
					 MSR_IA32_MISC_ENABLE_XD_DISABLE);
		if (disable) {
			wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable & ~disable);
			bootsym(trampoline_misc_enable_off) |= disable;
		}

		if (disable & MSR_IA32_MISC_ENABLE_LIMIT_CPUID)
			printk(KERN_INFO "revised cpuid level: %d\n",
			       cpuid_eax(0));
		if (disable & MSR_IA32_MISC_ENABLE_XD_DISABLE) {
			write_efer(read_efer() | EFER_NX);
			printk(KERN_INFO
			       "re-enabled NX (Execute Disable) protection\n");
		}
	}

	/* CPUID workaround for Intel 0F33/0F34 CPU */
	if (boot_cpu_data.x86 == 0xF && boot_cpu_data.x86_model == 3 &&
	    (boot_cpu_data.x86_mask == 3 || boot_cpu_data.x86_mask == 4))
		paddr_bits = 36;

	if (c == &boot_cpu_data)
		intel_init_levelling();

	if (test_bit(X86_FEATURE_CPUID_FAULTING, boot_cpu_data.x86_capability))
		__set_bit(X86_FEATURE_CPUID_FAULTING, c->x86_capability);

	intel_ctxt_switch_levelling(NULL);
}

/*
 * P4 Xeon errata 037 workaround.
 * Hardware prefetcher may cause stale data to be loaded into the cache.
 *
 * Xeon 7400 erratum AAI65 (and further newer Xeons)
 * MONITOR/MWAIT may have excessive false wakeups
 */
static void Intel_errata_workarounds(struct cpuinfo_x86 *c)
{
	unsigned long lo, hi;

	if ((c->x86 == 15) && (c->x86_model == 1) && (c->x86_mask == 1)) {
		rdmsr (MSR_IA32_MISC_ENABLE, lo, hi);
		if ((lo & (1<<9)) == 0) {
			printk (KERN_INFO "CPU: C0 stepping P4 Xeon detected.\n");
			printk (KERN_INFO "CPU: Disabling hardware prefetching (Errata 037)\n");
			lo |= (1<<9);	/* Disable hw prefetching */
			wrmsr (MSR_IA32_MISC_ENABLE, lo, hi);
		}
	}

	if (c->x86 == 6 && cpu_has_clflush &&
	    (c->x86_model == 29 || c->x86_model == 46 || c->x86_model == 47))
		__set_bit(X86_FEATURE_CLFLUSH_MONITOR, c->x86_capability);
}


/*
 * find out the number of processor cores on the die
 */
static int num_cpu_cores(struct cpuinfo_x86 *c)
{
	unsigned int eax, ebx, ecx, edx;

	if (c->cpuid_level < 4)
		return 1;

	/* Intel has a non-standard dependency on %ecx for this CPUID level. */
	cpuid_count(4, 0, &eax, &ebx, &ecx, &edx);
	if (eax & 0x1f)
		return ((eax >> 26) + 1);
	else
		return 1;
}

static void init_intel(struct cpuinfo_x86 *c)
{
	unsigned int l2 = 0;

	/* Detect the extended topology information if available */
	detect_extended_topology(c);

	select_idle_routine(c);
	l2 = init_intel_cacheinfo(c);
	if (c->cpuid_level > 9) {
		unsigned eax = cpuid_eax(10);
		/* Check for version and the number of counters */
		if ((eax & 0xff) && (((eax>>8) & 0xff) > 1))
			__set_bit(X86_FEATURE_ARCH_PERFMON, c->x86_capability);
	}

	if ( !cpu_has(c, X86_FEATURE_XTOPOLOGY) )
	{
		c->x86_max_cores = num_cpu_cores(c);
		detect_ht(c);
	}

	/* Work around errata */
	Intel_errata_workarounds(c);

	if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
		(c->x86 == 0x6 && c->x86_model >= 0x0e))
		__set_bit(X86_FEATURE_CONSTANT_TSC, c->x86_capability);
	if (cpu_has(c, X86_FEATURE_ITSC)) {
		__set_bit(X86_FEATURE_CONSTANT_TSC, c->x86_capability);
		__set_bit(X86_FEATURE_NONSTOP_TSC, c->x86_capability);
		__set_bit(X86_FEATURE_TSC_RELIABLE, c->x86_capability);
	}
	if ( opt_arat &&
	     ( c->cpuid_level >= 0x00000006 ) &&
	     ( cpuid_eax(0x00000006) & (1u<<2) ) )
		__set_bit(X86_FEATURE_ARAT, c->x86_capability);
}

static const struct cpu_dev intel_cpu_dev = {
	.c_vendor	= "Intel",
	.c_ident 	= { "GenuineIntel" },
	.c_early_init	= early_init_intel,
	.c_init		= init_intel,
};

int __init intel_cpu_init(void)
{
	cpu_devs[X86_VENDOR_INTEL] = &intel_cpu_dev;
	return 0;
}

// arch_initcall(intel_cpu_init);

