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linux/arch/powerpc/kvm/emulate_loadstore.c
Jordan Niethe 797a5af8fc KVM: PPC: Reduce reliance on analyse_instr() in mmio emulation 
Commit 7092360399 ("KVM: PPC: Reimplement non-SIMD LOAD/STORE
instruction mmio emulation with analyse_instr() input") and
commit 2b33cb585f ("KVM: PPC: Reimplement LOAD_FP/STORE_FP instruction
mmio emulation with analyse_instr() input") made
kvmppc_emulate_loadstore() use the results from analyse_instr() for
instruction emulation. In particular the effective address from
analyse_instr() is used for UPDATE type instructions and fact that
op.val is all ready endian corrected is used in the STORE case.

However, these changes now have some negative implications for the
nestedv2 case.  For analyse_instr() to determine the correct effective
address, the GPRs must be loaded from the L0. This is not needed as
vcpu->arch.vaddr_accessed is already set. Change back to using
vcpu->arch.vaddr_accessed.

In the STORE case, use kvmppc_get_gpr() value instead of the op.val.
kvmppc_get_gpr() will reload from the L0 if needed in the nestedv2 case.
This means if a byte reversal is needed must now be passed to
kvmppc_handle_store() like in the kvmppc_handle_load() case.

This means the call to kvmhv_nestedv2_reload_ptregs() can be avoided as
there is no concern about op.val being stale. Drop the call to
kvmhv_nestedv2_mark_dirty_ptregs() as without the call to
kvmhv_nestedv2_reload_ptregs(), stale state could be marked as valid.

This is fine as the required marking things dirty is already handled for
the UPDATE case by the call to kvmppc_set_gpr(). For LOADs, it is
handled in kvmppc_complete_mmio_load(). This is called either directly
in __kvmppc_handle_load() if the load can be handled in KVM, or on the
next kvm_arch_vcpu_ioctl_run() if an exit was required.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231201132618.555031-12-vaibhav@linux.ibm.com
2023-12-07 23:33:08 +11:00

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// 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, kvmppc_get_msr(vcpu) & SRR1_PREFIXED);
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, kvmppc_get_msr(vcpu) & SRR1_PREFIXED);
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, kvmppc_get_msr(vcpu) & SRR1_PREFIXED);
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)
{
ppc_inst_t inst;
enum emulation_result emulated = EMULATE_FAIL;
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 = kvmppc_get_msr(vcpu);
if (analyse_instr(&op, &vcpu->arch.regs, inst) == 0) {
int type = op.type & INSTR_TYPE_MASK;
int size = GETSIZE(op.type);
vcpu->mmio_is_write = OP_IS_STORE(type);
switch (type) {
case LOAD: {
int instr_byte_swap = op.type & BYTEREV;
if (op.type & SIGNEXT)
emulated = kvmppc_handle_loads(vcpu,
op.reg, size, !instr_byte_swap);
else
emulated = kvmppc_handle_load(vcpu,
op.reg, size, !instr_byte_swap);
if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
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(vcpu,
KVM_MMIO_REG_FPR|op.reg, size, 1);
else
emulated = kvmppc_handle_load(vcpu,
KVM_MMIO_REG_FPR|op.reg, size, 1);
if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
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(vcpu,
KVM_MMIO_REG_VMX|op.reg,
8, 1);
} else {
vcpu->arch.mmio_vmx_copy_nums = 1;
emulated = kvmppc_handle_vmx_load(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(vcpu,
KVM_MMIO_REG_VSX|op.reg, io_size_each,
1, op.type & SIGNEXT);
break;
}
#endif
case STORE: {
int instr_byte_swap = op.type & BYTEREV;
emulated = kvmppc_handle_store(vcpu, kvmppc_get_gpr(vcpu, op.reg),
size, !instr_byte_swap);
if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
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(vcpu,
kvmppc_get_fpr(vcpu, op.reg), size, 1);
if ((op.type & UPDATE) && (emulated != EMULATE_FAIL))
kvmppc_set_gpr(vcpu, op.update_reg, vcpu->arch.vaddr_accessed);
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(vcpu,
op.reg, 8, 1);
} else {
vcpu->arch.mmio_vmx_copy_nums = 1;
emulated = kvmppc_handle_vmx_store(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(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;
}
}
trace_kvm_ppc_instr(ppc_inst_val(inst), kvmppc_get_pc(vcpu), emulated);
/* Advance past emulated instruction. */
if (emulated != EMULATE_FAIL)
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + ppc_inst_len(inst));
return emulated;
}
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