emulate_loadstore.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright IBM Corp. 2007
 * Copyright 2011 Freescale Semiconductor, Inc.
 *
 * Authors: Hollis Blanchard <hollisb@us.ibm.com>
 */

#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kvm_host.h>
#include <linux/clockchips.h>

#include <asm/reg.h>
#include <asm/time.h>
#include <asm/byteorder.h>
#include <asm/kvm_ppc.h>
#include <asm/disassemble.h>
#include <asm/ppc-opcode.h>
#include <asm/sstep.h>
#include "timing.h"
#include "trace.h"

#ifdef CONFIG_PPC_FPU
static bool kvmppc_check_fp_disabled(struct kvm_vcpu *vcpu)
{
	if (!(kvmppc_get_msr(vcpu) & MSR_FP)) {
		kvmppc_core_queue_fpunavail(vcpu);
		return true;
	}

	return false;
}
#endif /* CONFIG_PPC_FPU */

#ifdef CONFIG_VSX
static bool kvmppc_check_vsx_disabled(struct kvm_vcpu *vcpu)
{
	if (!(kvmppc_get_msr(vcpu) & MSR_VSX)) {
		kvmppc_core_queue_vsx_unavail(vcpu);
		return true;
	}

	return false;
}
#endif /* CONFIG_VSX */

#ifdef CONFIG_ALTIVEC
static bool kvmppc_check_altivec_disabled(struct kvm_vcpu *vcpu)
{
	if (!(kvmppc_get_msr(vcpu) & MSR_VEC)) {
		kvmppc_core_queue_vec_unavail(vcpu);
		return true;
	}

	return false;
}
#endif /* CONFIG_ALTIVEC */

/*
 * XXX to do:
 * lfiwax, lfiwzx
 * vector loads and stores
 *
 * Instructions that trap when used on cache-inhibited mappings
 * are not emulated here: multiple and string instructions,
 * lq/stq, and the load-reserve/store-conditional instructions.
 */
int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;
	u32 inst;
	enum emulation_result emulated = EMULATE_FAIL;
	int advance = 1;
	struct instruction_op op;

	/* this default type might be overwritten by subcategories */
	kvmppc_set_exit_type(vcpu, EMULATED_INST_EXITS);

	emulated = kvmppc_get_last_inst(vcpu, INST_GENERIC, &inst);
	if (emulated != EMULATE_DONE)
		return emulated;

	vcpu->arch.mmio_vsx_copy_nums = 0;
	vcpu->arch.mmio_vsx_offset = 0;
	vcpu->arch.mmio_copy_type = KVMPPC_VSX_COPY_NONE;
	vcpu->arch.mmio_sp64_extend = 0;
	vcpu->arch.mmio_sign_extend = 0;
	vcpu->arch.mmio_vmx_copy_nums = 0;
	vcpu->arch.mmio_vmx_offset = 0;
	vcpu->arch.mmio_host_swabbed = 0;

	emulated = EMULATE_FAIL;
	vcpu->arch.regs.msr = vcpu->arch.shared->msr;
	if (analyse_instr(&op, &vcpu->arch.regs, inst) == 0) {
		int type = op.type & INSTR_TYPE_MASK;
		int size = GETSIZE(op.type);

		switch (type) {
		case LOAD:  {
			int instr_byte_swap = op.type & BYTEREV;

			if (op.type & SIGNEXT)
				emulated = kvmppc_handle_loads(run, vcpu,
						op.reg, size, !instr_byte_swap);
			else
				emulated = kvmppc_handle_load(run, vcpu,
						op.reg, size, !instr_byte_swap);

			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);

			break;
		}
#ifdef CONFIG_PPC_FPU
		case LOAD_FP:
			if (kvmppc_check_fp_disabled(vcpu))
				return EMULATE_DONE;

			if (op.type & FPCONV)
				vcpu->arch.mmio_sp64_extend = 1;

			if (op.type & SIGNEXT)
				emulated = kvmppc_handle_loads(run, vcpu,
					     KVM_MMIO_REG_FPR|op.reg, size, 1);
			else
				emulated = kvmppc_handle_load(run, vcpu,
					     KVM_MMIO_REG_FPR|op.reg, size, 1);

			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);

			break;
#endif
#ifdef CONFIG_ALTIVEC
		case LOAD_VMX:
			if (kvmppc_check_altivec_disabled(vcpu))
				return EMULATE_DONE;

			/* Hardware enforces alignment of VMX accesses */
			vcpu->arch.vaddr_accessed &= ~((unsigned long)size - 1);
			vcpu->arch.paddr_accessed &= ~((unsigned long)size - 1);

			if (size == 16) { /* lvx */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_DWORD;
			} else if (size == 4) { /* lvewx  */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_WORD;
			} else if (size == 2) { /* lvehx  */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_HWORD;
			} else if (size == 1) { /* lvebx  */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_BYTE;
			} else
				break;

			vcpu->arch.mmio_vmx_offset =
				(vcpu->arch.vaddr_accessed & 0xf)/size;

			if (size == 16) {
				vcpu->arch.mmio_vmx_copy_nums = 2;
				emulated = kvmppc_handle_vmx_load(run,
						vcpu, KVM_MMIO_REG_VMX|op.reg,
						8, 1);
			} else {
				vcpu->arch.mmio_vmx_copy_nums = 1;
				emulated = kvmppc_handle_vmx_load(run, vcpu,
						KVM_MMIO_REG_VMX|op.reg,
						size, 1);
			}
			break;
#endif
#ifdef CONFIG_VSX
		case LOAD_VSX: {
			int io_size_each;

			if (op.vsx_flags & VSX_CHECK_VEC) {
				if (kvmppc_check_altivec_disabled(vcpu))
					return EMULATE_DONE;
			} else {
				if (kvmppc_check_vsx_disabled(vcpu))
					return EMULATE_DONE;
			}

			if (op.vsx_flags & VSX_FPCONV)
				vcpu->arch.mmio_sp64_extend = 1;

			if (op.element_size == 8)  {
				if (op.vsx_flags & VSX_SPLAT)
					vcpu->arch.mmio_copy_type =
						KVMPPC_VSX_COPY_DWORD_LOAD_DUMP;
				else
					vcpu->arch.mmio_copy_type =
						KVMPPC_VSX_COPY_DWORD;
			} else if (op.element_size == 4) {
				if (op.vsx_flags & VSX_SPLAT)
					vcpu->arch.mmio_copy_type =
						KVMPPC_VSX_COPY_WORD_LOAD_DUMP;
				else
					vcpu->arch.mmio_copy_type =
						KVMPPC_VSX_COPY_WORD;
			} else
				break;

			if (size < op.element_size) {
				/* precision convert case: lxsspx, etc */
				vcpu->arch.mmio_vsx_copy_nums = 1;
				io_size_each = size;
			} else { /* lxvw4x, lxvd2x, etc */
				vcpu->arch.mmio_vsx_copy_nums =
					size/op.element_size;
				io_size_each = op.element_size;
			}

			emulated = kvmppc_handle_vsx_load(run, vcpu,
					KVM_MMIO_REG_VSX|op.reg, io_size_each,
					1, op.type & SIGNEXT);
			break;
		}
#endif
		case STORE:
			/* if need byte reverse, op.val has been reversed by
			 * analyse_instr().
			 */
			emulated = kvmppc_handle_store(run, vcpu, op.val,
					size, 1);

			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);

			break;
#ifdef CONFIG_PPC_FPU
		case STORE_FP:
			if (kvmppc_check_fp_disabled(vcpu))
				return EMULATE_DONE;

			/* The FP registers need to be flushed so that
			 * kvmppc_handle_store() can read actual FP vals
			 * from vcpu->arch.
			 */
			if (vcpu->kvm->arch.kvm_ops->giveup_ext)
				vcpu->kvm->arch.kvm_ops->giveup_ext(vcpu,
						MSR_FP);

			if (op.type & FPCONV)
				vcpu->arch.mmio_sp64_extend = 1;

			emulated = kvmppc_handle_store(run, vcpu,
					VCPU_FPR(vcpu, op.reg), size, 1);

			if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
				kvmppc_set_gpr(vcpu, op.update_reg, op.ea);

			break;
#endif
#ifdef CONFIG_ALTIVEC
		case STORE_VMX:
			if (kvmppc_check_altivec_disabled(vcpu))
				return EMULATE_DONE;

			/* Hardware enforces alignment of VMX accesses. */
			vcpu->arch.vaddr_accessed &= ~((unsigned long)size - 1);
			vcpu->arch.paddr_accessed &= ~((unsigned long)size - 1);

			if (vcpu->kvm->arch.kvm_ops->giveup_ext)
				vcpu->kvm->arch.kvm_ops->giveup_ext(vcpu,
						MSR_VEC);
			if (size == 16) { /* stvx */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_DWORD;
			} else if (size == 4) { /* stvewx  */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_WORD;
			} else if (size == 2) { /* stvehx  */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_HWORD;
			} else if (size == 1) { /* stvebx  */
				vcpu->arch.mmio_copy_type =
						KVMPPC_VMX_COPY_BYTE;
			} else
				break;

			vcpu->arch.mmio_vmx_offset =
				(vcpu->arch.vaddr_accessed & 0xf)/size;

			if (size == 16) {
				vcpu->arch.mmio_vmx_copy_nums = 2;
				emulated = kvmppc_handle_vmx_store(run,
						vcpu, op.reg, 8, 1);
			} else {
				vcpu->arch.mmio_vmx_copy_nums = 1;
				emulated = kvmppc_handle_vmx_store(run,
						vcpu, op.reg, size, 1);
			}

			break;
#endif
#ifdef CONFIG_VSX
		case STORE_VSX: {
			int io_size_each;

			if (op.vsx_flags & VSX_CHECK_VEC) {
				if (kvmppc_check_altivec_disabled(vcpu))
					return EMULATE_DONE;
			} else {
				if (kvmppc_check_vsx_disabled(vcpu))
					return EMULATE_DONE;
			}

			if (vcpu->kvm->arch.kvm_ops->giveup_ext)
				vcpu->kvm->arch.kvm_ops->giveup_ext(vcpu,
						MSR_VSX);

			if (op.vsx_flags & VSX_FPCONV)
				vcpu->arch.mmio_sp64_extend = 1;

			if (op.element_size == 8)
				vcpu->arch.mmio_copy_type =
						KVMPPC_VSX_COPY_DWORD;
			else if (op.element_size == 4)
				vcpu->arch.mmio_copy_type =
						KVMPPC_VSX_COPY_WORD;
			else
				break;

			if (size < op.element_size) {
				/* precise conversion case, like stxsspx */
				vcpu->arch.mmio_vsx_copy_nums = 1;
				io_size_each = size;
			} else { /* stxvw4x, stxvd2x, etc */
				vcpu->arch.mmio_vsx_copy_nums =
						size/op.element_size;
				io_size_each = op.element_size;
			}

			emulated = kvmppc_handle_vsx_store(run, vcpu,
					op.reg, io_size_each, 1);
			break;
		}
#endif
		case CACHEOP:
			/* Do nothing. The guest is performing dcbi because
			 * hardware DMA is not snooped by the dcache, but
			 * emulated DMA either goes through the dcache as
			 * normal writes, or the host kernel has handled dcache
			 * coherence.
			 */
			emulated = EMULATE_DONE;
			break;
		default:
			break;
		}
	}

	if (emulated == EMULATE_FAIL) {
		advance = 0;
		kvmppc_core_queue_program(vcpu, 0);
	}

	trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);

	/* Advance past emulated instruction. */
	if (advance)
		kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);

	return emulated;
}