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2025-08-12 22:16:57 +02:00

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C
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2023 MediaTek Inc.
*/
#include <linux/clocksource.h>
#include <linux/kernel.h>
#include <linux/timekeeping.h>
#include <linux/soc/mediatek/gzvm_drv.h>
#include "gzvm_arch_common.h"
#define GZVM_PTP_VIRT_COUNTER 0
#define GZVM_PTP_PHYS_COUNTER 1
/**
* gzvm_handle_ptp_time() - Sync time between host and guest VM
* @vcpu: Pointer to struct gzvm_vcpu_run in userspace
* @counter: Counter type from guest VM
* Return: Always return 0 because there are no cases of failure
*
* The following register values will be passed to the guest VM
* for time synchronization:
* regs->x0 (upper 32 bits) wall clock time
* regs->x1 (lower 32 bits) wall clock time
* regs->x2 (upper 32 bits) cycles
* regs->x3 (lower 32 bits) cycles
*/
static int gzvm_handle_ptp_time(struct gzvm_vcpu *vcpu, int counter)
{
struct system_time_snapshot snapshot;
u64 cycles = 0;
ktime_get_snapshot(&snapshot);
switch (counter) {
case GZVM_PTP_VIRT_COUNTER:
cycles = snapshot.cycles -
le64_to_cpu(vcpu->hwstate->vtimer_offset);
break;
case GZVM_PTP_PHYS_COUNTER:
cycles = snapshot.cycles;
break;
default:
break;
}
vcpu->run->hypercall.args[0] = upper_32_bits(snapshot.real);
vcpu->run->hypercall.args[1] = lower_32_bits(snapshot.real);
vcpu->run->hypercall.args[2] = upper_32_bits(cycles);
vcpu->run->hypercall.args[3] = lower_32_bits(cycles);
return 0;
}
/**
* gzvm_arch_handle_guest_hvc() - Handle architecture-related guest hvc
* @vcpu: Pointer to struct gzvm_vcpu_run in userspace
* Return:
* * true - This hvc has been processed, no need to back to VMM.
* * false - This hvc has not been processed, require userspace.
*/
bool gzvm_arch_handle_guest_hvc(struct gzvm_vcpu *vcpu)
{
int ret, counter;
switch (vcpu->run->hypercall.args[0]) {
case GZVM_HVC_PTP:
counter = vcpu->run->hypercall.args[1];
ret = gzvm_handle_ptp_time(vcpu, counter);
return (ret == 0) ? true : false;
default:
break;
}
return false;
}