forked from Minki/linux
8bf3129503
Loongson-3 can use lddir/ldpte instuctions to accelerate page table walking, so use them to lookup gpa_mm.pgd. Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com> Signed-off-by: Huacai Chen <chenhc@lemote.com> Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> Message-Id: <1590220602-3547-6-git-send-email-chenhc@lemote.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
961 lines
26 KiB
C
961 lines
26 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Generation of main entry point for the guest, exception handling.
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*
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* Copyright (C) 2012 MIPS Technologies, Inc.
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* Authors: Sanjay Lal <sanjayl@kymasys.com>
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*
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* Copyright (C) 2016 Imagination Technologies Ltd.
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*/
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#include <linux/kvm_host.h>
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#include <linux/log2.h>
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#include <asm/mmu_context.h>
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#include <asm/msa.h>
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#include <asm/setup.h>
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#include <asm/tlbex.h>
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#include <asm/uasm.h>
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/* Register names */
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#define ZERO 0
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#define AT 1
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#define V0 2
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#define V1 3
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#define A0 4
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#define A1 5
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#if _MIPS_SIM == _MIPS_SIM_ABI32
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#define T0 8
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#define T1 9
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#define T2 10
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#define T3 11
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#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */
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#if _MIPS_SIM == _MIPS_SIM_ABI64 || _MIPS_SIM == _MIPS_SIM_NABI32
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#define T0 12
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#define T1 13
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#define T2 14
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#define T3 15
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#endif /* _MIPS_SIM == _MIPS_SIM_ABI64 || _MIPS_SIM == _MIPS_SIM_NABI32 */
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#define S0 16
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#define S1 17
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#define T9 25
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#define K0 26
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#define K1 27
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#define GP 28
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#define SP 29
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#define RA 31
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/* Some CP0 registers */
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#define C0_PWBASE 5, 5
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#define C0_HWRENA 7, 0
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#define C0_BADVADDR 8, 0
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#define C0_BADINSTR 8, 1
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#define C0_BADINSTRP 8, 2
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#define C0_PGD 9, 7
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#define C0_ENTRYHI 10, 0
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#define C0_GUESTCTL1 10, 4
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#define C0_STATUS 12, 0
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#define C0_GUESTCTL0 12, 6
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#define C0_CAUSE 13, 0
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#define C0_EPC 14, 0
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#define C0_EBASE 15, 1
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#define C0_CONFIG5 16, 5
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#define C0_DDATA_LO 28, 3
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#define C0_ERROREPC 30, 0
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#define CALLFRAME_SIZ 32
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#ifdef CONFIG_64BIT
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#define ST0_KX_IF_64 ST0_KX
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#else
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#define ST0_KX_IF_64 0
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#endif
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static unsigned int scratch_vcpu[2] = { C0_DDATA_LO };
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static unsigned int scratch_tmp[2] = { C0_ERROREPC };
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enum label_id {
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label_fpu_1 = 1,
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label_msa_1,
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label_return_to_host,
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label_kernel_asid,
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label_exit_common,
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};
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UASM_L_LA(_fpu_1)
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UASM_L_LA(_msa_1)
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UASM_L_LA(_return_to_host)
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UASM_L_LA(_kernel_asid)
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UASM_L_LA(_exit_common)
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static void *kvm_mips_build_enter_guest(void *addr);
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static void *kvm_mips_build_ret_from_exit(void *addr);
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static void *kvm_mips_build_ret_to_guest(void *addr);
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static void *kvm_mips_build_ret_to_host(void *addr);
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/*
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* The version of this function in tlbex.c uses current_cpu_type(), but for KVM
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* we assume symmetry.
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*/
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static int c0_kscratch(void)
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{
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switch (boot_cpu_type()) {
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case CPU_XLP:
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case CPU_XLR:
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return 22;
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default:
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return 31;
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}
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}
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/**
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* kvm_mips_entry_setup() - Perform global setup for entry code.
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*
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* Perform global setup for entry code, such as choosing a scratch register.
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*
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* Returns: 0 on success.
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* -errno on failure.
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*/
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int kvm_mips_entry_setup(void)
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{
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/*
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* We prefer to use KScratchN registers if they are available over the
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* defaults above, which may not work on all cores.
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*/
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unsigned int kscratch_mask = cpu_data[0].kscratch_mask;
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if (pgd_reg != -1)
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kscratch_mask &= ~BIT(pgd_reg);
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/* Pick a scratch register for storing VCPU */
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if (kscratch_mask) {
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scratch_vcpu[0] = c0_kscratch();
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scratch_vcpu[1] = ffs(kscratch_mask) - 1;
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kscratch_mask &= ~BIT(scratch_vcpu[1]);
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}
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/* Pick a scratch register to use as a temp for saving state */
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if (kscratch_mask) {
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scratch_tmp[0] = c0_kscratch();
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scratch_tmp[1] = ffs(kscratch_mask) - 1;
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kscratch_mask &= ~BIT(scratch_tmp[1]);
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}
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return 0;
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}
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static void kvm_mips_build_save_scratch(u32 **p, unsigned int tmp,
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unsigned int frame)
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{
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/* Save the VCPU scratch register value in cp0_epc of the stack frame */
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UASM_i_MFC0(p, tmp, scratch_vcpu[0], scratch_vcpu[1]);
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UASM_i_SW(p, tmp, offsetof(struct pt_regs, cp0_epc), frame);
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/* Save the temp scratch register value in cp0_cause of stack frame */
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if (scratch_tmp[0] == c0_kscratch()) {
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UASM_i_MFC0(p, tmp, scratch_tmp[0], scratch_tmp[1]);
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UASM_i_SW(p, tmp, offsetof(struct pt_regs, cp0_cause), frame);
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}
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}
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static void kvm_mips_build_restore_scratch(u32 **p, unsigned int tmp,
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unsigned int frame)
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{
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/*
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* Restore host scratch register values saved by
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* kvm_mips_build_save_scratch().
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*/
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UASM_i_LW(p, tmp, offsetof(struct pt_regs, cp0_epc), frame);
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UASM_i_MTC0(p, tmp, scratch_vcpu[0], scratch_vcpu[1]);
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if (scratch_tmp[0] == c0_kscratch()) {
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UASM_i_LW(p, tmp, offsetof(struct pt_regs, cp0_cause), frame);
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UASM_i_MTC0(p, tmp, scratch_tmp[0], scratch_tmp[1]);
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}
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}
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/**
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* build_set_exc_base() - Assemble code to write exception base address.
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* @p: Code buffer pointer.
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* @reg: Source register (generated code may set WG bit in @reg).
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*
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* Assemble code to modify the exception base address in the EBase register,
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* using the appropriately sized access and setting the WG bit if necessary.
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*/
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static inline void build_set_exc_base(u32 **p, unsigned int reg)
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{
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if (cpu_has_ebase_wg) {
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/* Set WG so that all the bits get written */
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uasm_i_ori(p, reg, reg, MIPS_EBASE_WG);
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UASM_i_MTC0(p, reg, C0_EBASE);
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} else {
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uasm_i_mtc0(p, reg, C0_EBASE);
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}
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}
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/**
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* kvm_mips_build_vcpu_run() - Assemble function to start running a guest VCPU.
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* @addr: Address to start writing code.
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*
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* Assemble the start of the vcpu_run function to run a guest VCPU. The function
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* conforms to the following prototype:
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*
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* int vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu);
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*
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* The exit from the guest and return to the caller is handled by the code
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* generated by kvm_mips_build_ret_to_host().
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*
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* Returns: Next address after end of written function.
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*/
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void *kvm_mips_build_vcpu_run(void *addr)
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{
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u32 *p = addr;
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unsigned int i;
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/*
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* A0: run
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* A1: vcpu
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*/
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/* k0/k1 not being used in host kernel context */
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UASM_i_ADDIU(&p, K1, SP, -(int)sizeof(struct pt_regs));
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for (i = 16; i < 32; ++i) {
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if (i == 24)
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i = 28;
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UASM_i_SW(&p, i, offsetof(struct pt_regs, regs[i]), K1);
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}
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/* Save host status */
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uasm_i_mfc0(&p, V0, C0_STATUS);
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UASM_i_SW(&p, V0, offsetof(struct pt_regs, cp0_status), K1);
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/* Save scratch registers, will be used to store pointer to vcpu etc */
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kvm_mips_build_save_scratch(&p, V1, K1);
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/* VCPU scratch register has pointer to vcpu */
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UASM_i_MTC0(&p, A1, scratch_vcpu[0], scratch_vcpu[1]);
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/* Offset into vcpu->arch */
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UASM_i_ADDIU(&p, K1, A1, offsetof(struct kvm_vcpu, arch));
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/*
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* Save the host stack to VCPU, used for exception processing
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* when we exit from the Guest
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*/
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UASM_i_SW(&p, SP, offsetof(struct kvm_vcpu_arch, host_stack), K1);
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/* Save the kernel gp as well */
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UASM_i_SW(&p, GP, offsetof(struct kvm_vcpu_arch, host_gp), K1);
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/*
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* Setup status register for running the guest in UM, interrupts
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* are disabled
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*/
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UASM_i_LA(&p, K0, ST0_EXL | KSU_USER | ST0_BEV | ST0_KX_IF_64);
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uasm_i_mtc0(&p, K0, C0_STATUS);
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uasm_i_ehb(&p);
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/* load up the new EBASE */
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UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, guest_ebase), K1);
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build_set_exc_base(&p, K0);
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/*
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* Now that the new EBASE has been loaded, unset BEV, set
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* interrupt mask as it was but make sure that timer interrupts
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* are enabled
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*/
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uasm_i_addiu(&p, K0, ZERO, ST0_EXL | KSU_USER | ST0_IE | ST0_KX_IF_64);
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uasm_i_andi(&p, V0, V0, ST0_IM);
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uasm_i_or(&p, K0, K0, V0);
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uasm_i_mtc0(&p, K0, C0_STATUS);
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uasm_i_ehb(&p);
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p = kvm_mips_build_enter_guest(p);
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return p;
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}
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/**
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* kvm_mips_build_enter_guest() - Assemble code to resume guest execution.
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* @addr: Address to start writing code.
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*
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* Assemble the code to resume guest execution. This code is common between the
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* initial entry into the guest from the host, and returning from the exit
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* handler back to the guest.
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*
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* Returns: Next address after end of written function.
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*/
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static void *kvm_mips_build_enter_guest(void *addr)
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{
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u32 *p = addr;
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unsigned int i;
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struct uasm_label labels[2];
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struct uasm_reloc relocs[2];
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struct uasm_label __maybe_unused *l = labels;
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struct uasm_reloc __maybe_unused *r = relocs;
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memset(labels, 0, sizeof(labels));
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memset(relocs, 0, sizeof(relocs));
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/* Set Guest EPC */
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UASM_i_LW(&p, T0, offsetof(struct kvm_vcpu_arch, pc), K1);
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UASM_i_MTC0(&p, T0, C0_EPC);
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#ifdef CONFIG_KVM_MIPS_VZ
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/* Save normal linux process pgd (VZ guarantees pgd_reg is set) */
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if (cpu_has_ldpte)
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UASM_i_MFC0(&p, K0, C0_PWBASE);
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else
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UASM_i_MFC0(&p, K0, c0_kscratch(), pgd_reg);
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UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu_arch, host_pgd), K1);
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/*
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* Set up KVM GPA pgd.
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* This does roughly the same as TLBMISS_HANDLER_SETUP_PGD():
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* - call tlbmiss_handler_setup_pgd(mm->pgd)
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* - write mm->pgd into CP0_PWBase
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*
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* We keep S0 pointing at struct kvm so we can load the ASID below.
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*/
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UASM_i_LW(&p, S0, (int)offsetof(struct kvm_vcpu, kvm) -
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(int)offsetof(struct kvm_vcpu, arch), K1);
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UASM_i_LW(&p, A0, offsetof(struct kvm, arch.gpa_mm.pgd), S0);
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UASM_i_LA(&p, T9, (unsigned long)tlbmiss_handler_setup_pgd);
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uasm_i_jalr(&p, RA, T9);
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/* delay slot */
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if (cpu_has_htw)
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UASM_i_MTC0(&p, A0, C0_PWBASE);
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else
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uasm_i_nop(&p);
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/* Set GM bit to setup eret to VZ guest context */
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uasm_i_addiu(&p, V1, ZERO, 1);
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uasm_i_mfc0(&p, K0, C0_GUESTCTL0);
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uasm_i_ins(&p, K0, V1, MIPS_GCTL0_GM_SHIFT, 1);
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uasm_i_mtc0(&p, K0, C0_GUESTCTL0);
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if (cpu_has_guestid) {
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/*
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* Set root mode GuestID, so that root TLB refill handler can
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* use the correct GuestID in the root TLB.
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*/
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/* Get current GuestID */
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uasm_i_mfc0(&p, T0, C0_GUESTCTL1);
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/* Set GuestCtl1.RID = GuestCtl1.ID */
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uasm_i_ext(&p, T1, T0, MIPS_GCTL1_ID_SHIFT,
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MIPS_GCTL1_ID_WIDTH);
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uasm_i_ins(&p, T0, T1, MIPS_GCTL1_RID_SHIFT,
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MIPS_GCTL1_RID_WIDTH);
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uasm_i_mtc0(&p, T0, C0_GUESTCTL1);
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/* GuestID handles dealiasing so we don't need to touch ASID */
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goto skip_asid_restore;
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}
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/* Root ASID Dealias (RAD) */
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/* Save host ASID */
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UASM_i_MFC0(&p, K0, C0_ENTRYHI);
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UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu_arch, host_entryhi),
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K1);
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/* Set the root ASID for the Guest */
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UASM_i_ADDIU(&p, T1, S0,
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offsetof(struct kvm, arch.gpa_mm.context.asid));
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#else
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/* Set the ASID for the Guest Kernel or User */
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UASM_i_LW(&p, T0, offsetof(struct kvm_vcpu_arch, cop0), K1);
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UASM_i_LW(&p, T0, offsetof(struct mips_coproc, reg[MIPS_CP0_STATUS][0]),
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T0);
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uasm_i_andi(&p, T0, T0, KSU_USER | ST0_ERL | ST0_EXL);
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uasm_i_xori(&p, T0, T0, KSU_USER);
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uasm_il_bnez(&p, &r, T0, label_kernel_asid);
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UASM_i_ADDIU(&p, T1, K1, offsetof(struct kvm_vcpu_arch,
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guest_kernel_mm.context.asid));
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/* else user */
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UASM_i_ADDIU(&p, T1, K1, offsetof(struct kvm_vcpu_arch,
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guest_user_mm.context.asid));
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uasm_l_kernel_asid(&l, p);
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#endif
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/* t1: contains the base of the ASID array, need to get the cpu id */
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/* smp_processor_id */
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uasm_i_lw(&p, T2, offsetof(struct thread_info, cpu), GP);
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/* index the ASID array */
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uasm_i_sll(&p, T2, T2, ilog2(sizeof(long)));
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UASM_i_ADDU(&p, T3, T1, T2);
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UASM_i_LW(&p, K0, 0, T3);
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#ifdef CONFIG_MIPS_ASID_BITS_VARIABLE
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/*
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* reuse ASID array offset
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* cpuinfo_mips is a multiple of sizeof(long)
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*/
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uasm_i_addiu(&p, T3, ZERO, sizeof(struct cpuinfo_mips)/sizeof(long));
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uasm_i_mul(&p, T2, T2, T3);
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UASM_i_LA_mostly(&p, AT, (long)&cpu_data[0].asid_mask);
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UASM_i_ADDU(&p, AT, AT, T2);
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UASM_i_LW(&p, T2, uasm_rel_lo((long)&cpu_data[0].asid_mask), AT);
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uasm_i_and(&p, K0, K0, T2);
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#else
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uasm_i_andi(&p, K0, K0, MIPS_ENTRYHI_ASID);
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#endif
|
|
|
|
#ifndef CONFIG_KVM_MIPS_VZ
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|
/*
|
|
* Set up KVM T&E GVA pgd.
|
|
* This does roughly the same as TLBMISS_HANDLER_SETUP_PGD():
|
|
* - call tlbmiss_handler_setup_pgd(mm->pgd)
|
|
* - but skips write into CP0_PWBase for now
|
|
*/
|
|
UASM_i_LW(&p, A0, (int)offsetof(struct mm_struct, pgd) -
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(int)offsetof(struct mm_struct, context.asid), T1);
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|
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UASM_i_LA(&p, T9, (unsigned long)tlbmiss_handler_setup_pgd);
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uasm_i_jalr(&p, RA, T9);
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uasm_i_mtc0(&p, K0, C0_ENTRYHI);
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#else
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/* Set up KVM VZ root ASID (!guestid) */
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uasm_i_mtc0(&p, K0, C0_ENTRYHI);
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skip_asid_restore:
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#endif
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uasm_i_ehb(&p);
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|
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/* Disable RDHWR access */
|
|
uasm_i_mtc0(&p, ZERO, C0_HWRENA);
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|
|
/* load the guest context from VCPU and return */
|
|
for (i = 1; i < 32; ++i) {
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|
/* Guest k0/k1 loaded later */
|
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if (i == K0 || i == K1)
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continue;
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UASM_i_LW(&p, i, offsetof(struct kvm_vcpu_arch, gprs[i]), K1);
|
|
}
|
|
|
|
#ifndef CONFIG_CPU_MIPSR6
|
|
/* Restore hi/lo */
|
|
UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, hi), K1);
|
|
uasm_i_mthi(&p, K0);
|
|
|
|
UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, lo), K1);
|
|
uasm_i_mtlo(&p, K0);
|
|
#endif
|
|
|
|
/* Restore the guest's k0/k1 registers */
|
|
UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, gprs[K0]), K1);
|
|
UASM_i_LW(&p, K1, offsetof(struct kvm_vcpu_arch, gprs[K1]), K1);
|
|
|
|
/* Jump to guest */
|
|
uasm_i_eret(&p);
|
|
|
|
uasm_resolve_relocs(relocs, labels);
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_build_tlb_refill_exception() - Assemble TLB refill handler.
|
|
* @addr: Address to start writing code.
|
|
* @handler: Address of common handler (within range of @addr).
|
|
*
|
|
* Assemble TLB refill exception fast path handler for guest execution.
|
|
*
|
|
* Returns: Next address after end of written function.
|
|
*/
|
|
void *kvm_mips_build_tlb_refill_exception(void *addr, void *handler)
|
|
{
|
|
u32 *p = addr;
|
|
struct uasm_label labels[2];
|
|
struct uasm_reloc relocs[2];
|
|
#ifndef CONFIG_CPU_LOONGSON64
|
|
struct uasm_label *l = labels;
|
|
struct uasm_reloc *r = relocs;
|
|
#endif
|
|
|
|
memset(labels, 0, sizeof(labels));
|
|
memset(relocs, 0, sizeof(relocs));
|
|
|
|
/* Save guest k1 into scratch register */
|
|
UASM_i_MTC0(&p, K1, scratch_tmp[0], scratch_tmp[1]);
|
|
|
|
/* Get the VCPU pointer from the VCPU scratch register */
|
|
UASM_i_MFC0(&p, K1, scratch_vcpu[0], scratch_vcpu[1]);
|
|
|
|
/* Save guest k0 into VCPU structure */
|
|
UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu, arch.gprs[K0]), K1);
|
|
|
|
/*
|
|
* Some of the common tlbex code uses current_cpu_type(). For KVM we
|
|
* assume symmetry and just disable preemption to silence the warning.
|
|
*/
|
|
preempt_disable();
|
|
|
|
#ifdef CONFIG_CPU_LOONGSON64
|
|
UASM_i_MFC0(&p, K1, C0_PGD);
|
|
uasm_i_lddir(&p, K0, K1, 3); /* global page dir */
|
|
#ifndef __PAGETABLE_PMD_FOLDED
|
|
uasm_i_lddir(&p, K1, K0, 1); /* middle page dir */
|
|
#endif
|
|
uasm_i_ldpte(&p, K1, 0); /* even */
|
|
uasm_i_ldpte(&p, K1, 1); /* odd */
|
|
uasm_i_tlbwr(&p);
|
|
#else
|
|
/*
|
|
* Now for the actual refill bit. A lot of this can be common with the
|
|
* Linux TLB refill handler, however we don't need to handle so many
|
|
* cases. We only need to handle user mode refills, and user mode runs
|
|
* with 32-bit addressing.
|
|
*
|
|
* Therefore the branch to label_vmalloc generated by build_get_pmde64()
|
|
* that isn't resolved should never actually get taken and is harmless
|
|
* to leave in place for now.
|
|
*/
|
|
|
|
#ifdef CONFIG_64BIT
|
|
build_get_pmde64(&p, &l, &r, K0, K1); /* get pmd in K1 */
|
|
#else
|
|
build_get_pgde32(&p, K0, K1); /* get pgd in K1 */
|
|
#endif
|
|
|
|
/* we don't support huge pages yet */
|
|
|
|
build_get_ptep(&p, K0, K1);
|
|
build_update_entries(&p, K0, K1);
|
|
build_tlb_write_entry(&p, &l, &r, tlb_random);
|
|
#endif
|
|
|
|
preempt_enable();
|
|
|
|
/* Get the VCPU pointer from the VCPU scratch register again */
|
|
UASM_i_MFC0(&p, K1, scratch_vcpu[0], scratch_vcpu[1]);
|
|
|
|
/* Restore the guest's k0/k1 registers */
|
|
UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu, arch.gprs[K0]), K1);
|
|
uasm_i_ehb(&p);
|
|
UASM_i_MFC0(&p, K1, scratch_tmp[0], scratch_tmp[1]);
|
|
|
|
/* Jump to guest */
|
|
uasm_i_eret(&p);
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_build_exception() - Assemble first level guest exception handler.
|
|
* @addr: Address to start writing code.
|
|
* @handler: Address of common handler (within range of @addr).
|
|
*
|
|
* Assemble exception vector code for guest execution. The generated vector will
|
|
* branch to the common exception handler generated by kvm_mips_build_exit().
|
|
*
|
|
* Returns: Next address after end of written function.
|
|
*/
|
|
void *kvm_mips_build_exception(void *addr, void *handler)
|
|
{
|
|
u32 *p = addr;
|
|
struct uasm_label labels[2];
|
|
struct uasm_reloc relocs[2];
|
|
struct uasm_label *l = labels;
|
|
struct uasm_reloc *r = relocs;
|
|
|
|
memset(labels, 0, sizeof(labels));
|
|
memset(relocs, 0, sizeof(relocs));
|
|
|
|
/* Save guest k1 into scratch register */
|
|
UASM_i_MTC0(&p, K1, scratch_tmp[0], scratch_tmp[1]);
|
|
|
|
/* Get the VCPU pointer from the VCPU scratch register */
|
|
UASM_i_MFC0(&p, K1, scratch_vcpu[0], scratch_vcpu[1]);
|
|
UASM_i_ADDIU(&p, K1, K1, offsetof(struct kvm_vcpu, arch));
|
|
|
|
/* Save guest k0 into VCPU structure */
|
|
UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu_arch, gprs[K0]), K1);
|
|
|
|
/* Branch to the common handler */
|
|
uasm_il_b(&p, &r, label_exit_common);
|
|
uasm_i_nop(&p);
|
|
|
|
uasm_l_exit_common(&l, handler);
|
|
uasm_resolve_relocs(relocs, labels);
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_build_exit() - Assemble common guest exit handler.
|
|
* @addr: Address to start writing code.
|
|
*
|
|
* Assemble the generic guest exit handling code. This is called by the
|
|
* exception vectors (generated by kvm_mips_build_exception()), and calls
|
|
* kvm_mips_handle_exit(), then either resumes the guest or returns to the host
|
|
* depending on the return value.
|
|
*
|
|
* Returns: Next address after end of written function.
|
|
*/
|
|
void *kvm_mips_build_exit(void *addr)
|
|
{
|
|
u32 *p = addr;
|
|
unsigned int i;
|
|
struct uasm_label labels[3];
|
|
struct uasm_reloc relocs[3];
|
|
struct uasm_label *l = labels;
|
|
struct uasm_reloc *r = relocs;
|
|
|
|
memset(labels, 0, sizeof(labels));
|
|
memset(relocs, 0, sizeof(relocs));
|
|
|
|
/*
|
|
* Generic Guest exception handler. We end up here when the guest
|
|
* does something that causes a trap to kernel mode.
|
|
*
|
|
* Both k0/k1 registers will have already been saved (k0 into the vcpu
|
|
* structure, and k1 into the scratch_tmp register).
|
|
*
|
|
* The k1 register will already contain the kvm_vcpu_arch pointer.
|
|
*/
|
|
|
|
/* Start saving Guest context to VCPU */
|
|
for (i = 0; i < 32; ++i) {
|
|
/* Guest k0/k1 saved later */
|
|
if (i == K0 || i == K1)
|
|
continue;
|
|
UASM_i_SW(&p, i, offsetof(struct kvm_vcpu_arch, gprs[i]), K1);
|
|
}
|
|
|
|
#ifndef CONFIG_CPU_MIPSR6
|
|
/* We need to save hi/lo and restore them on the way out */
|
|
uasm_i_mfhi(&p, T0);
|
|
UASM_i_SW(&p, T0, offsetof(struct kvm_vcpu_arch, hi), K1);
|
|
|
|
uasm_i_mflo(&p, T0);
|
|
UASM_i_SW(&p, T0, offsetof(struct kvm_vcpu_arch, lo), K1);
|
|
#endif
|
|
|
|
/* Finally save guest k1 to VCPU */
|
|
uasm_i_ehb(&p);
|
|
UASM_i_MFC0(&p, T0, scratch_tmp[0], scratch_tmp[1]);
|
|
UASM_i_SW(&p, T0, offsetof(struct kvm_vcpu_arch, gprs[K1]), K1);
|
|
|
|
/* Now that context has been saved, we can use other registers */
|
|
|
|
/* Restore vcpu */
|
|
UASM_i_MFC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]);
|
|
|
|
/* Restore run (vcpu->run) */
|
|
UASM_i_LW(&p, S0, offsetof(struct kvm_vcpu, run), S1);
|
|
|
|
/*
|
|
* Save Host level EPC, BadVaddr and Cause to VCPU, useful to process
|
|
* the exception
|
|
*/
|
|
UASM_i_MFC0(&p, K0, C0_EPC);
|
|
UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu_arch, pc), K1);
|
|
|
|
UASM_i_MFC0(&p, K0, C0_BADVADDR);
|
|
UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu_arch, host_cp0_badvaddr),
|
|
K1);
|
|
|
|
uasm_i_mfc0(&p, K0, C0_CAUSE);
|
|
uasm_i_sw(&p, K0, offsetof(struct kvm_vcpu_arch, host_cp0_cause), K1);
|
|
|
|
if (cpu_has_badinstr) {
|
|
uasm_i_mfc0(&p, K0, C0_BADINSTR);
|
|
uasm_i_sw(&p, K0, offsetof(struct kvm_vcpu_arch,
|
|
host_cp0_badinstr), K1);
|
|
}
|
|
|
|
if (cpu_has_badinstrp) {
|
|
uasm_i_mfc0(&p, K0, C0_BADINSTRP);
|
|
uasm_i_sw(&p, K0, offsetof(struct kvm_vcpu_arch,
|
|
host_cp0_badinstrp), K1);
|
|
}
|
|
|
|
/* Now restore the host state just enough to run the handlers */
|
|
|
|
/* Switch EBASE to the one used by Linux */
|
|
/* load up the host EBASE */
|
|
uasm_i_mfc0(&p, V0, C0_STATUS);
|
|
|
|
uasm_i_lui(&p, AT, ST0_BEV >> 16);
|
|
uasm_i_or(&p, K0, V0, AT);
|
|
|
|
uasm_i_mtc0(&p, K0, C0_STATUS);
|
|
uasm_i_ehb(&p);
|
|
|
|
UASM_i_LA_mostly(&p, K0, (long)&ebase);
|
|
UASM_i_LW(&p, K0, uasm_rel_lo((long)&ebase), K0);
|
|
build_set_exc_base(&p, K0);
|
|
|
|
if (raw_cpu_has_fpu) {
|
|
/*
|
|
* If FPU is enabled, save FCR31 and clear it so that later
|
|
* ctc1's don't trigger FPE for pending exceptions.
|
|
*/
|
|
uasm_i_lui(&p, AT, ST0_CU1 >> 16);
|
|
uasm_i_and(&p, V1, V0, AT);
|
|
uasm_il_beqz(&p, &r, V1, label_fpu_1);
|
|
uasm_i_nop(&p);
|
|
uasm_i_cfc1(&p, T0, 31);
|
|
uasm_i_sw(&p, T0, offsetof(struct kvm_vcpu_arch, fpu.fcr31),
|
|
K1);
|
|
uasm_i_ctc1(&p, ZERO, 31);
|
|
uasm_l_fpu_1(&l, p);
|
|
}
|
|
|
|
if (cpu_has_msa) {
|
|
/*
|
|
* If MSA is enabled, save MSACSR and clear it so that later
|
|
* instructions don't trigger MSAFPE for pending exceptions.
|
|
*/
|
|
uasm_i_mfc0(&p, T0, C0_CONFIG5);
|
|
uasm_i_ext(&p, T0, T0, 27, 1); /* MIPS_CONF5_MSAEN */
|
|
uasm_il_beqz(&p, &r, T0, label_msa_1);
|
|
uasm_i_nop(&p);
|
|
uasm_i_cfcmsa(&p, T0, MSA_CSR);
|
|
uasm_i_sw(&p, T0, offsetof(struct kvm_vcpu_arch, fpu.msacsr),
|
|
K1);
|
|
uasm_i_ctcmsa(&p, MSA_CSR, ZERO);
|
|
uasm_l_msa_1(&l, p);
|
|
}
|
|
|
|
#ifdef CONFIG_KVM_MIPS_VZ
|
|
/* Restore host ASID */
|
|
if (!cpu_has_guestid) {
|
|
UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu_arch, host_entryhi),
|
|
K1);
|
|
UASM_i_MTC0(&p, K0, C0_ENTRYHI);
|
|
}
|
|
|
|
/*
|
|
* Set up normal Linux process pgd.
|
|
* This does roughly the same as TLBMISS_HANDLER_SETUP_PGD():
|
|
* - call tlbmiss_handler_setup_pgd(mm->pgd)
|
|
* - write mm->pgd into CP0_PWBase
|
|
*/
|
|
UASM_i_LW(&p, A0,
|
|
offsetof(struct kvm_vcpu_arch, host_pgd), K1);
|
|
UASM_i_LA(&p, T9, (unsigned long)tlbmiss_handler_setup_pgd);
|
|
uasm_i_jalr(&p, RA, T9);
|
|
/* delay slot */
|
|
if (cpu_has_htw)
|
|
UASM_i_MTC0(&p, A0, C0_PWBASE);
|
|
else
|
|
uasm_i_nop(&p);
|
|
|
|
/* Clear GM bit so we don't enter guest mode when EXL is cleared */
|
|
uasm_i_mfc0(&p, K0, C0_GUESTCTL0);
|
|
uasm_i_ins(&p, K0, ZERO, MIPS_GCTL0_GM_SHIFT, 1);
|
|
uasm_i_mtc0(&p, K0, C0_GUESTCTL0);
|
|
|
|
/* Save GuestCtl0 so we can access GExcCode after CPU migration */
|
|
uasm_i_sw(&p, K0,
|
|
offsetof(struct kvm_vcpu_arch, host_cp0_guestctl0), K1);
|
|
|
|
if (cpu_has_guestid) {
|
|
/*
|
|
* Clear root mode GuestID, so that root TLB operations use the
|
|
* root GuestID in the root TLB.
|
|
*/
|
|
uasm_i_mfc0(&p, T0, C0_GUESTCTL1);
|
|
/* Set GuestCtl1.RID = MIPS_GCTL1_ROOT_GUESTID (i.e. 0) */
|
|
uasm_i_ins(&p, T0, ZERO, MIPS_GCTL1_RID_SHIFT,
|
|
MIPS_GCTL1_RID_WIDTH);
|
|
uasm_i_mtc0(&p, T0, C0_GUESTCTL1);
|
|
}
|
|
#endif
|
|
|
|
/* Now that the new EBASE has been loaded, unset BEV and KSU_USER */
|
|
uasm_i_addiu(&p, AT, ZERO, ~(ST0_EXL | KSU_USER | ST0_IE));
|
|
uasm_i_and(&p, V0, V0, AT);
|
|
uasm_i_lui(&p, AT, ST0_CU0 >> 16);
|
|
uasm_i_or(&p, V0, V0, AT);
|
|
#ifdef CONFIG_64BIT
|
|
uasm_i_ori(&p, V0, V0, ST0_SX | ST0_UX);
|
|
#endif
|
|
uasm_i_mtc0(&p, V0, C0_STATUS);
|
|
uasm_i_ehb(&p);
|
|
|
|
/* Load up host GP */
|
|
UASM_i_LW(&p, GP, offsetof(struct kvm_vcpu_arch, host_gp), K1);
|
|
|
|
/* Need a stack before we can jump to "C" */
|
|
UASM_i_LW(&p, SP, offsetof(struct kvm_vcpu_arch, host_stack), K1);
|
|
|
|
/* Saved host state */
|
|
UASM_i_ADDIU(&p, SP, SP, -(int)sizeof(struct pt_regs));
|
|
|
|
/*
|
|
* XXXKYMA do we need to load the host ASID, maybe not because the
|
|
* kernel entries are marked GLOBAL, need to verify
|
|
*/
|
|
|
|
/* Restore host scratch registers, as we'll have clobbered them */
|
|
kvm_mips_build_restore_scratch(&p, K0, SP);
|
|
|
|
/* Restore RDHWR access */
|
|
UASM_i_LA_mostly(&p, K0, (long)&hwrena);
|
|
uasm_i_lw(&p, K0, uasm_rel_lo((long)&hwrena), K0);
|
|
uasm_i_mtc0(&p, K0, C0_HWRENA);
|
|
|
|
/* Jump to handler */
|
|
/*
|
|
* XXXKYMA: not sure if this is safe, how large is the stack??
|
|
* Now jump to the kvm_mips_handle_exit() to see if we can deal
|
|
* with this in the kernel
|
|
*/
|
|
uasm_i_move(&p, A0, S0);
|
|
uasm_i_move(&p, A1, S1);
|
|
UASM_i_LA(&p, T9, (unsigned long)kvm_mips_handle_exit);
|
|
uasm_i_jalr(&p, RA, T9);
|
|
UASM_i_ADDIU(&p, SP, SP, -CALLFRAME_SIZ);
|
|
|
|
uasm_resolve_relocs(relocs, labels);
|
|
|
|
p = kvm_mips_build_ret_from_exit(p);
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_build_ret_from_exit() - Assemble guest exit return handler.
|
|
* @addr: Address to start writing code.
|
|
*
|
|
* Assemble the code to handle the return from kvm_mips_handle_exit(), either
|
|
* resuming the guest or returning to the host depending on the return value.
|
|
*
|
|
* Returns: Next address after end of written function.
|
|
*/
|
|
static void *kvm_mips_build_ret_from_exit(void *addr)
|
|
{
|
|
u32 *p = addr;
|
|
struct uasm_label labels[2];
|
|
struct uasm_reloc relocs[2];
|
|
struct uasm_label *l = labels;
|
|
struct uasm_reloc *r = relocs;
|
|
|
|
memset(labels, 0, sizeof(labels));
|
|
memset(relocs, 0, sizeof(relocs));
|
|
|
|
/* Return from handler Make sure interrupts are disabled */
|
|
uasm_i_di(&p, ZERO);
|
|
uasm_i_ehb(&p);
|
|
|
|
/*
|
|
* XXXKYMA: k0/k1 could have been blown away if we processed
|
|
* an exception while we were handling the exception from the
|
|
* guest, reload k1
|
|
*/
|
|
|
|
uasm_i_move(&p, K1, S1);
|
|
UASM_i_ADDIU(&p, K1, K1, offsetof(struct kvm_vcpu, arch));
|
|
|
|
/*
|
|
* Check return value, should tell us if we are returning to the
|
|
* host (handle I/O etc)or resuming the guest
|
|
*/
|
|
uasm_i_andi(&p, T0, V0, RESUME_HOST);
|
|
uasm_il_bnez(&p, &r, T0, label_return_to_host);
|
|
uasm_i_nop(&p);
|
|
|
|
p = kvm_mips_build_ret_to_guest(p);
|
|
|
|
uasm_l_return_to_host(&l, p);
|
|
p = kvm_mips_build_ret_to_host(p);
|
|
|
|
uasm_resolve_relocs(relocs, labels);
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_build_ret_to_guest() - Assemble code to return to the guest.
|
|
* @addr: Address to start writing code.
|
|
*
|
|
* Assemble the code to handle return from the guest exit handler
|
|
* (kvm_mips_handle_exit()) back to the guest.
|
|
*
|
|
* Returns: Next address after end of written function.
|
|
*/
|
|
static void *kvm_mips_build_ret_to_guest(void *addr)
|
|
{
|
|
u32 *p = addr;
|
|
|
|
/* Put the saved pointer to vcpu (s1) back into the scratch register */
|
|
UASM_i_MTC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]);
|
|
|
|
/* Load up the Guest EBASE to minimize the window where BEV is set */
|
|
UASM_i_LW(&p, T0, offsetof(struct kvm_vcpu_arch, guest_ebase), K1);
|
|
|
|
/* Switch EBASE back to the one used by KVM */
|
|
uasm_i_mfc0(&p, V1, C0_STATUS);
|
|
uasm_i_lui(&p, AT, ST0_BEV >> 16);
|
|
uasm_i_or(&p, K0, V1, AT);
|
|
uasm_i_mtc0(&p, K0, C0_STATUS);
|
|
uasm_i_ehb(&p);
|
|
build_set_exc_base(&p, T0);
|
|
|
|
/* Setup status register for running guest in UM */
|
|
uasm_i_ori(&p, V1, V1, ST0_EXL | KSU_USER | ST0_IE);
|
|
UASM_i_LA(&p, AT, ~(ST0_CU0 | ST0_MX | ST0_SX | ST0_UX));
|
|
uasm_i_and(&p, V1, V1, AT);
|
|
uasm_i_mtc0(&p, V1, C0_STATUS);
|
|
uasm_i_ehb(&p);
|
|
|
|
p = kvm_mips_build_enter_guest(p);
|
|
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* kvm_mips_build_ret_to_host() - Assemble code to return to the host.
|
|
* @addr: Address to start writing code.
|
|
*
|
|
* Assemble the code to handle return from the guest exit handler
|
|
* (kvm_mips_handle_exit()) back to the host, i.e. to the caller of the vcpu_run
|
|
* function generated by kvm_mips_build_vcpu_run().
|
|
*
|
|
* Returns: Next address after end of written function.
|
|
*/
|
|
static void *kvm_mips_build_ret_to_host(void *addr)
|
|
{
|
|
u32 *p = addr;
|
|
unsigned int i;
|
|
|
|
/* EBASE is already pointing to Linux */
|
|
UASM_i_LW(&p, K1, offsetof(struct kvm_vcpu_arch, host_stack), K1);
|
|
UASM_i_ADDIU(&p, K1, K1, -(int)sizeof(struct pt_regs));
|
|
|
|
/*
|
|
* r2/v0 is the return code, shift it down by 2 (arithmetic)
|
|
* to recover the err code
|
|
*/
|
|
uasm_i_sra(&p, K0, V0, 2);
|
|
uasm_i_move(&p, V0, K0);
|
|
|
|
/* Load context saved on the host stack */
|
|
for (i = 16; i < 31; ++i) {
|
|
if (i == 24)
|
|
i = 28;
|
|
UASM_i_LW(&p, i, offsetof(struct pt_regs, regs[i]), K1);
|
|
}
|
|
|
|
/* Restore RDHWR access */
|
|
UASM_i_LA_mostly(&p, K0, (long)&hwrena);
|
|
uasm_i_lw(&p, K0, uasm_rel_lo((long)&hwrena), K0);
|
|
uasm_i_mtc0(&p, K0, C0_HWRENA);
|
|
|
|
/* Restore RA, which is the address we will return to */
|
|
UASM_i_LW(&p, RA, offsetof(struct pt_regs, regs[RA]), K1);
|
|
uasm_i_jr(&p, RA);
|
|
uasm_i_nop(&p);
|
|
|
|
return p;
|
|
}
|
|
|