/*
 *
 * Copyright (c) 2009, Microsoft Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 *
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include "osd.h"
#include "logging.h"
#include "VmbusPrivate.h"

/* Globals */

/* The one and only */
struct hv_context gHvContext = {
	.SynICInitialized	= false,
	.HypercallPage		= NULL,
	.SignalEventParam	= NULL,
	.SignalEventBuffer	= NULL,
};


/*++

Name:
	HvQueryHypervisorPresence()

Description:
	Query the cpuid for presense of windows hypervisor

--*/
static int
HvQueryHypervisorPresence (
    void
    )
{
    unsigned int eax;
    unsigned int ebx;
    unsigned int ecx;
    unsigned int edx;
    unsigned int op;

    eax = 0;
    ebx = 0;
    ecx = 0;
    edx = 0;
    op = HvCpuIdFunctionVersionAndFeatures;
    cpuid(op, &eax, &ebx, &ecx, &edx);

	return (ecx & HV_PRESENT_BIT);
}


/*++

Name:
	HvQueryHypervisorInfo()

Description:
	Get version info of the windows hypervisor

--*/
static int
HvQueryHypervisorInfo (
    void
    )
{
    unsigned int eax;
    unsigned int ebx;
    unsigned int ecx;
    unsigned int edx;
    unsigned int maxLeaf;
    unsigned int op;

    /*
     * Its assumed that this is called after confirming that Viridian
     * is present. Query id and revision.
     */


    eax = 0;
    ebx = 0;
    ecx = 0;
    edx = 0;
    op = HvCpuIdFunctionHvVendorAndMaxFunction;
    cpuid(op, &eax, &ebx, &ecx, &edx);

    DPRINT_INFO(VMBUS, "Vendor ID: %c%c%c%c%c%c%c%c%c%c%c%c",
	   (ebx & 0xFF),
	   ((ebx >> 8) & 0xFF),
	   ((ebx >> 16) & 0xFF),
	   ((ebx >> 24) & 0xFF),
	   (ecx & 0xFF),
	   ((ecx >> 8) & 0xFF),
	   ((ecx >> 16) & 0xFF),
	   ((ecx >> 24) & 0xFF),
	   (edx & 0xFF),
	   ((edx >> 8) & 0xFF),
	   ((edx >> 16) & 0xFF),
	   ((edx >> 24) & 0xFF));

    maxLeaf = eax;
    eax = 0;
    ebx = 0;
    ecx = 0;
    edx = 0;
    op = HvCpuIdFunctionHvInterface;
    cpuid(op, &eax, &ebx, &ecx, &edx);

    DPRINT_INFO(VMBUS, "Interface ID: %c%c%c%c",
	   (eax & 0xFF),
	   ((eax >> 8) & 0xFF),
	   ((eax >> 16) & 0xFF),
	   ((eax >> 24) & 0xFF));

	 if (maxLeaf >= HvCpuIdFunctionMsHvVersion) {
	eax = 0;
	ebx = 0;
	ecx = 0;
	edx = 0;
	op = HvCpuIdFunctionMsHvVersion;
	cpuid(op, &eax, &ebx, &ecx, &edx);
	DPRINT_INFO(VMBUS, "OS Build:%d-%d.%d-%d-%d.%d",
	       eax,
	       ebx >> 16,
	       ebx & 0xFFFF,
	       ecx,
	       edx >> 24,
	       edx & 0xFFFFFF);
    }
    return maxLeaf;
}


/*++

Name:
	HvDoHypercall()

Description:
	Invoke the specified hypercall

--*/
static u64
HvDoHypercall (
    u64  Control,
    void*   Input,
    void*   Output
    )
{
#ifdef CONFIG_X86_64
    u64 hvStatus=0;
	u64 inputAddress = (Input)? virt_to_phys(Input) : 0;
	u64 outputAddress = (Output)? virt_to_phys(Output) : 0;
    volatile void* hypercallPage = gHvContext.HypercallPage;

    DPRINT_DBG(VMBUS, "Hypercall <control %llx input phys %llx virt %p output phys %llx virt %p hypercall %p>",
		Control,
		inputAddress,
		Input,
		outputAddress,
		Output,
		hypercallPage);

	__asm__ __volatile__ ("mov %0, %%r8" : : "r" (outputAddress):  "r8");
	__asm__ __volatile__ ("call *%3" : "=a"(hvStatus): "c" (Control), "d" (inputAddress), "m" (hypercallPage));

    DPRINT_DBG(VMBUS, "Hypercall <return %llx>",  hvStatus);

    return hvStatus;

#else

    u32 controlHi = Control >> 32;
    u32 controlLo = Control & 0xFFFFFFFF;
    u32 hvStatusHi = 1;
    u32 hvStatusLo = 1;
    u64 inputAddress = (Input) ? virt_to_phys(Input) : 0;
    u32 inputAddressHi = inputAddress >> 32;
    u32 inputAddressLo = inputAddress & 0xFFFFFFFF;
	u64 outputAddress = (Output) ? virt_to_phys(Output) : 0;
    u32 outputAddressHi = outputAddress >> 32;
    u32 outputAddressLo = outputAddress & 0xFFFFFFFF;
    volatile void* hypercallPage = gHvContext.HypercallPage;

    DPRINT_DBG(VMBUS, "Hypercall <control %llx input %p output %p>",
		Control,
		Input,
		Output);

	__asm__ __volatile__ ("call *%8" : "=d"(hvStatusHi), "=a"(hvStatusLo) : "d" (controlHi), "a" (controlLo), "b" (inputAddressHi), "c" (inputAddressLo), "D"(outputAddressHi), "S"(outputAddressLo), "m" (hypercallPage));


    DPRINT_DBG(VMBUS, "Hypercall <return %llx>",  hvStatusLo | ((u64)hvStatusHi << 32));

    return (hvStatusLo | ((u64)hvStatusHi << 32));
#endif /* x86_64 */
}

/*++

Name:
	HvInit()

Description:
	Main initialization routine. This routine must be called
	before any other routines in here are called

--*/
int HvInit (void)
{
	int ret=0;
    int maxLeaf;
	union hv_x64_msr_hypercall_contents hypercallMsr;
	void *virtAddr = NULL;

	DPRINT_ENTER(VMBUS);

	memset(gHvContext.synICEventPage, 0, sizeof(void *) * MAX_NUM_CPUS);
	memset(gHvContext.synICMessagePage, 0, sizeof(void *) * MAX_NUM_CPUS);

	if (!HvQueryHypervisorPresence())
	{
		DPRINT_ERR(VMBUS, "No Windows hypervisor detected!!");
		goto Cleanup;
	}

	DPRINT_INFO(VMBUS, "Windows hypervisor detected! Retrieving more info...");

    maxLeaf = HvQueryHypervisorInfo();
    /* HvQueryHypervisorFeatures(maxLeaf); */

	/* Determine if we are running on xenlinux (ie x2v shim) or native linux */
	rdmsrl(HV_X64_MSR_GUEST_OS_ID, gHvContext.GuestId);
	if (gHvContext.GuestId == 0)
	{
		/* Write our OS info */
		wrmsrl(HV_X64_MSR_GUEST_OS_ID, HV_LINUX_GUEST_ID);

		gHvContext.GuestId = HV_LINUX_GUEST_ID;
	}

	/* See if the hypercall page is already set */
	rdmsrl(HV_X64_MSR_HYPERCALL, hypercallMsr.AsUINT64);
	if (gHvContext.GuestId == HV_LINUX_GUEST_ID)
	{
		/* Allocate the hypercall page memory */
		/* virtAddr = osd_PageAlloc(1); */
		virtAddr = osd_VirtualAllocExec(PAGE_SIZE);

		if (!virtAddr)
		{
			DPRINT_ERR(VMBUS, "unable to allocate hypercall page!!");
			goto Cleanup;
		}

		hypercallMsr.Enable = 1;
		/* hypercallMsr.GuestPhysicalAddress = virt_to_phys(virtAddr) >> PAGE_SHIFT; */
		hypercallMsr.GuestPhysicalAddress = vmalloc_to_pfn(virtAddr);
		wrmsrl(HV_X64_MSR_HYPERCALL, hypercallMsr.AsUINT64);

	/* Confirm that hypercall page did get setup. */
		hypercallMsr.AsUINT64 = 0;
		rdmsrl(HV_X64_MSR_HYPERCALL, hypercallMsr.AsUINT64);
		if (!hypercallMsr.Enable)
		{
			DPRINT_ERR(VMBUS, "unable to set hypercall page!!");
			goto Cleanup;
		}

		gHvContext.HypercallPage = virtAddr;
	}
	else
	{
		DPRINT_ERR(VMBUS, "Unknown guest id (0x%llx)!!", gHvContext.GuestId);
		goto Cleanup;
	}

	DPRINT_INFO(VMBUS, "Hypercall page VA=%p, PA=0x%0llx",
		    gHvContext.HypercallPage,
		    (u64)hypercallMsr.GuestPhysicalAddress << PAGE_SHIFT);

	/* Setup the global signal event param for the signal event hypercall */
	gHvContext.SignalEventBuffer = kmalloc(sizeof(struct hv_input_signal_event_buffer), GFP_KERNEL);
	if (!gHvContext.SignalEventBuffer)
	{
		goto Cleanup;
	}

	gHvContext.SignalEventParam = (struct hv_input_signal_event *)(ALIGN_UP((unsigned long)gHvContext.SignalEventBuffer, HV_HYPERCALL_PARAM_ALIGN));
	gHvContext.SignalEventParam->ConnectionId.Asu32 = 0;
	gHvContext.SignalEventParam->ConnectionId.u.Id = VMBUS_EVENT_CONNECTION_ID;
	gHvContext.SignalEventParam->FlagNumber = 0;
	gHvContext.SignalEventParam->RsvdZ = 0;

    /* DPRINT_DBG(VMBUS, "My id %llu", HvGetCurrentPartitionId()); */

	DPRINT_EXIT(VMBUS);

    return ret;

Cleanup:
	if (virtAddr)
	{
		if (hypercallMsr.Enable)
		{
			hypercallMsr.AsUINT64 = 0;
			wrmsrl(HV_X64_MSR_HYPERCALL, hypercallMsr.AsUINT64);
		}

		vfree(virtAddr);
	}
	ret = -1;
	DPRINT_EXIT(VMBUS);

	return ret;
}


/*++

Name:
	HvCleanup()

Description:
	Cleanup routine. This routine is called normally during driver unloading or exiting.

--*/
void HvCleanup (void)
{
	union hv_x64_msr_hypercall_contents hypercallMsr;

	DPRINT_ENTER(VMBUS);

	if (gHvContext.SignalEventBuffer)
	{
		kfree(gHvContext.SignalEventBuffer);
		gHvContext.SignalEventBuffer = NULL;
		gHvContext.SignalEventParam = NULL;
	}

	if (gHvContext.GuestId == HV_LINUX_GUEST_ID)
	{
		if (gHvContext.HypercallPage)
		{
			hypercallMsr.AsUINT64 = 0;
			wrmsrl(HV_X64_MSR_HYPERCALL, hypercallMsr.AsUINT64);
			vfree(gHvContext.HypercallPage);
			gHvContext.HypercallPage = NULL;
		}
	}

	DPRINT_EXIT(VMBUS);

}


/*++

Name:
	HvPostMessage()

Description:
	Post a message using the hypervisor message IPC. This
	involves a hypercall.

--*/
u16 HvPostMessage(union hv_connection_id connectionId,
		  enum hv_message_type messageType,
		  void *payload, size_t payloadSize)
{
	struct alignedInput {
		u64					alignment8;
		struct hv_input_post_message msg;
	};

	struct hv_input_post_message *alignedMsg;
	u16 status;
	unsigned long addr;

	if (payloadSize > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
	{
		return -1;
	}

	addr = (unsigned long)kmalloc(sizeof(struct alignedInput), GFP_ATOMIC);

	if (!addr)
	{
		return -1;
	}

	alignedMsg = (struct hv_input_post_message *)(ALIGN_UP(addr, HV_HYPERCALL_PARAM_ALIGN));

	alignedMsg->ConnectionId = connectionId;
	alignedMsg->MessageType = messageType;
	alignedMsg->PayloadSize = payloadSize;
	memcpy((void*)alignedMsg->Payload, payload, payloadSize);

	status = HvDoHypercall(HvCallPostMessage, alignedMsg, NULL) & 0xFFFF;

	kfree((void*)addr);

	return status;
}


/*++

Name:
	HvSignalEvent()

Description:
	Signal an event on the specified connection using the hypervisor event IPC. This
	involves a hypercall.

--*/
u16 HvSignalEvent(void)
{
	u16 status;

	status = HvDoHypercall(HvCallSignalEvent, gHvContext.SignalEventParam, NULL) & 0xFFFF;

	return status;
}


/*++

Name:
	HvSynicInit()

Description:
	Initialize the Synthethic Interrupt Controller. If it is already initialized by
	another entity (ie x2v shim), we need to retrieve the initialized message and event pages.
	Otherwise, we create and initialize the message and event pages.

--*/
int HvSynicInit (u32 irqVector)
{
	u64			version;
	union hv_synic_simp simp;
	union hv_synic_siefp siefp;
	union hv_synic_sint sharedSint;
	union hv_synic_scontrol sctrl;
	u64			guestID;
	int ret=0;

	DPRINT_ENTER(VMBUS);

	if (!gHvContext.HypercallPage)
	{
		DPRINT_EXIT(VMBUS);
		return ret;
	}

	/* Check the version */
	rdmsrl(HV_X64_MSR_SVERSION, version);

	DPRINT_INFO(VMBUS, "SynIC version: %llx", version);

	/* TODO: Handle SMP */
	if (gHvContext.GuestId == HV_XENLINUX_GUEST_ID)
	{
		DPRINT_INFO(VMBUS, "Skipping SIMP and SIEFP setup since it is already set.");

		rdmsrl(HV_X64_MSR_SIMP, simp.AsUINT64);
		rdmsrl(HV_X64_MSR_SIEFP, siefp.AsUINT64);

		DPRINT_DBG(VMBUS, "Simp: %llx, Sifep: %llx", simp.AsUINT64, siefp.AsUINT64);

		/* Determine if we are running on xenlinux (ie x2v shim) or native linux */
		rdmsrl(HV_X64_MSR_GUEST_OS_ID, guestID);
		if (guestID == HV_LINUX_GUEST_ID)
		{
			gHvContext.synICMessagePage[0] = phys_to_virt(simp.BaseSimpGpa << PAGE_SHIFT);
			gHvContext.synICEventPage[0] = phys_to_virt(siefp.BaseSiefpGpa << PAGE_SHIFT);
		}
		else
		{
			DPRINT_ERR(VMBUS, "unknown guest id!!");
			goto Cleanup;
		}
		DPRINT_DBG(VMBUS, "MAPPED: Simp: %p, Sifep: %p", gHvContext.synICMessagePage[0], gHvContext.synICEventPage[0]);
	}
	else
	{
		gHvContext.synICMessagePage[0] = osd_PageAlloc(1);
		if (gHvContext.synICMessagePage[0] == NULL)
		{
			DPRINT_ERR(VMBUS, "unable to allocate SYNIC message page!!");
			goto Cleanup;
		}

		gHvContext.synICEventPage[0] = osd_PageAlloc(1);
		if (gHvContext.synICEventPage[0] == NULL)
		{
			DPRINT_ERR(VMBUS, "unable to allocate SYNIC event page!!");
			goto Cleanup;
		}

		/* Setup the Synic's message page */
		rdmsrl(HV_X64_MSR_SIMP, simp.AsUINT64);
		simp.SimpEnabled = 1;
		simp.BaseSimpGpa = virt_to_phys(gHvContext.synICMessagePage[0]) >> PAGE_SHIFT;

		DPRINT_DBG(VMBUS, "HV_X64_MSR_SIMP msr set to: %llx", simp.AsUINT64);

		wrmsrl(HV_X64_MSR_SIMP, simp.AsUINT64);

		/* Setup the Synic's event page */
		rdmsrl(HV_X64_MSR_SIEFP, siefp.AsUINT64);
		siefp.SiefpEnabled = 1;
		siefp.BaseSiefpGpa = virt_to_phys(gHvContext.synICEventPage[0]) >> PAGE_SHIFT;

		DPRINT_DBG(VMBUS, "HV_X64_MSR_SIEFP msr set to: %llx", siefp.AsUINT64);

		wrmsrl(HV_X64_MSR_SIEFP, siefp.AsUINT64);
	}
    /* Setup the interception SINT. */
	/* wrmsrl((HV_X64_MSR_SINT0 + HV_SYNIC_INTERCEPTION_SINT_INDEX), */
    /*             interceptionSint.AsUINT64); */

    /* Setup the shared SINT. */
	rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, sharedSint.AsUINT64);

	sharedSint.AsUINT64 = 0;
	sharedSint.Vector = irqVector; /* HV_SHARED_SINT_IDT_VECTOR + 0x20; */
	sharedSint.Masked = false;
	sharedSint.AutoEoi = true;

	DPRINT_DBG(VMBUS, "HV_X64_MSR_SINT1 msr set to: %llx", sharedSint.AsUINT64);

	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, sharedSint.AsUINT64);

	/* Enable the global synic bit */
	rdmsrl(HV_X64_MSR_SCONTROL, sctrl.AsUINT64);
	sctrl.Enable = 1;

	wrmsrl(HV_X64_MSR_SCONTROL, sctrl.AsUINT64);

	gHvContext.SynICInitialized = true;

	DPRINT_EXIT(VMBUS);

	return ret;

Cleanup:
	ret = -1;

	if (gHvContext.GuestId == HV_LINUX_GUEST_ID)
	{
		if (gHvContext.synICEventPage[0])
		{
			osd_PageFree(gHvContext.synICEventPage[0],1);
		}

		if (gHvContext.synICMessagePage[0])
		{
			osd_PageFree(gHvContext.synICMessagePage[0], 1);
		}
	}

	DPRINT_EXIT(VMBUS);

	return ret;

}

/*++

Name:
	HvSynicCleanup()

Description:
	Cleanup routine for HvSynicInit().

--*/
void HvSynicCleanup(void)
{
	union hv_synic_sint sharedSint;
	union hv_synic_simp simp;
	union hv_synic_siefp siefp;

	DPRINT_ENTER(VMBUS);

	if (!gHvContext.SynICInitialized)
	{
		DPRINT_EXIT(VMBUS);
		return;
	}

	rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, sharedSint.AsUINT64);

	sharedSint.Masked = 1;

	/* Disable the interrupt */
	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, sharedSint.AsUINT64);

	/*
	 * Disable and free the resources only if we are running as
	 * native linux since in xenlinux, we are sharing the
	 * resources with the x2v shim
	 */
	if (gHvContext.GuestId == HV_LINUX_GUEST_ID)
	{
		rdmsrl(HV_X64_MSR_SIMP, simp.AsUINT64);
		simp.SimpEnabled = 0;
		simp.BaseSimpGpa = 0;

		wrmsrl(HV_X64_MSR_SIMP, simp.AsUINT64);

		rdmsrl(HV_X64_MSR_SIEFP, siefp.AsUINT64);
		siefp.SiefpEnabled = 0;
		siefp.BaseSiefpGpa = 0;

		wrmsrl(HV_X64_MSR_SIEFP, siefp.AsUINT64);

		osd_PageFree(gHvContext.synICMessagePage[0], 1);
		osd_PageFree(gHvContext.synICEventPage[0], 1);
	}

	DPRINT_EXIT(VMBUS);
}


/* eof */