/* * This file is subject to the terms and conditions of the GNU General Public * License . See the file " COPYING " in the main directory of this archive * for more details . * * Generation of main entry point for the guest , exception handling . * * Copyright ( C ) 2012 MIPS Technologies , Inc . * Authors : Sanjay Lal < sanjayl @ kymasys . com > * * Copyright ( C ) 2016 Imagination Technologies Ltd . #include <linux/kvm_host.h>#include <linux/log2.h>#include <asm /mipsregs.h>#include <asm /mmu_context.h>#include <asm /msa.h>#include <asm /regdef.h>#include <asm /setup.h>#include <asm /tlbex.h>#include <asm /uasm.h>#define CALLFRAME_SIZ 32 static unsigned int scratch_vcpu[2 ] = { C0_DDATALO };static unsigned int scratch_tmp[2 ] = { C0_ERROREPC };enum label_id {1 ,static void *kvm_mips_build_enter_guest(void *addr);static void *kvm_mips_build_ret_from_exit(void *addr);static void *kvm_mips_build_ret_to_guest(void *addr);static void *kvm_mips_build_ret_to_host(void *addr);/* * The version of this function in tlbex . c uses current_cpu_type ( ) , but for KVM * we assume symmetry . static int c0_kscratch(void )return 31 ;/** * kvm_mips_entry_setup ( ) - Perform global setup for entry code . * * Perform global setup for entry code , such as choosing a scratch register . * * Returns : 0 on success . * - errno on failure . int kvm_mips_entry_setup(void )/* * We prefer to use KScratchN registers if they are available over the * defaults above , which may not work on all cores . unsigned int kscratch_mask = cpu_data[0 ].kscratch_mask;if (pgd_reg != -1 )/* Pick a scratch register for storing VCPU */ if (kscratch_mask) {0 ] = c0_kscratch();1 ] = ffs(kscratch_mask) - 1 ;1 ]);/* Pick a scratch register to use as a temp for saving state */ if (kscratch_mask) {0 ] = c0_kscratch();1 ] = ffs(kscratch_mask) - 1 ;1 ]);return 0 ;static void kvm_mips_build_save_scratch(u32 **p, unsigned int tmp,unsigned int frame)/* Save the VCPU scratch register value in cp0_epc of the stack frame */ 0 ], scratch_vcpu[1 ]);struct pt_regs, cp0_epc), frame);/* Save the temp scratch register value in cp0_cause of stack frame */ if (scratch_tmp[0 ] == c0_kscratch()) {0 ], scratch_tmp[1 ]);struct pt_regs, cp0_cause), frame);static void kvm_mips_build_restore_scratch(u32 **p, unsigned int tmp,unsigned int frame)/* * Restore host scratch register values saved by * kvm_mips_build_save_scratch ( ) . struct pt_regs, cp0_epc), frame);0 ], scratch_vcpu[1 ]);if (scratch_tmp[0 ] == c0_kscratch()) {struct pt_regs, cp0_cause), frame);0 ], scratch_tmp[1 ]);/** * build_set_exc_base ( ) - Assemble code to write exception base address . * @ p : Code buffer pointer . * @ reg : Source register ( generated code may set WG bit in @ reg ) . * * Assemble code to modify the exception base address in the EBase register , * using the appropriately sized access and setting the WG bit if necessary . static inline void build_set_exc_base(u32 **p, unsigned int reg)if (cpu_has_ebase_wg) {/* Set WG so that all the bits get written */ else {/** * kvm_mips_build_vcpu_run ( ) - Assemble function to start running a guest VCPU . * @ addr : Address to start writing code . * * Assemble the start of the vcpu_run function to run a guest VCPU . The function * conforms to the following prototype : * * int vcpu_run ( struct kvm_vcpu * vcpu ) ; * * The exit from the guest and return to the caller is handled by the code * generated by kvm_mips_build_ret_to_host ( ) . * * Returns : Next address after end of written function . void *kvm_mips_build_vcpu_run(void *addr)unsigned int i;/* * GPR_A0 : vcpu /* k0/k1 not being used in host kernel context */ int )sizeof (struct pt_regs));for (i = 16 ; i < 32 ; ++i) {if (i == 24 )28 ;struct pt_regs, regs[i]), GPR_K1);/* Save host status */ struct pt_regs, cp0_status), GPR_K1);/* Save scratch registers, will be used to store pointer to vcpu etc */ /* VCPU scratch register has pointer to vcpu */ 0 ], scratch_vcpu[1 ]);/* Offset into vcpu->arch */ struct kvm_vcpu, arch));/* * Save the host stack to VCPU , used for exception processing * when we exit from the Guest struct kvm_vcpu_arch, host_stack), GPR_K1);/* Save the kernel gp as well */ struct kvm_vcpu_arch, host_gp), GPR_K1);/* * Setup status register for running the guest in UM , interrupts * are disabled /* load up the new EBASE */ struct kvm_vcpu_arch, guest_ebase), GPR_K1);/* * Now that the new EBASE has been loaded , unset BEV , set * interrupt mask as it was but make sure that timer interrupts * are enabled return p;/** * kvm_mips_build_enter_guest ( ) - Assemble code to resume guest execution . * @ addr : Address to start writing code . * * Assemble the code to resume guest execution . This code is common between the * initial entry into the guest from the host , and returning from the exit * handler back to the guest . * * Returns : Next address after end of written function . static void *kvm_mips_build_enter_guest(void *addr)unsigned int i;struct uasm_label labels[2 ];struct uasm_reloc relocs[2 ];struct uasm_label __maybe_unused *l = labels;struct uasm_reloc __maybe_unused *r = relocs;0 , sizeof (labels));0 , sizeof (relocs));/* Set Guest EPC */ struct kvm_vcpu_arch, pc), GPR_K1);/* Save normal linux process pgd (VZ guarantees pgd_reg is set) */ if (cpu_has_ldpte)else struct kvm_vcpu_arch, host_pgd), GPR_K1);/* * Set up KVM GPA pgd . * This does roughly the same as TLBMISS_HANDLER_SETUP_PGD ( ) : * - call tlbmiss_handler_setup_pgd ( mm - > pgd ) * - write mm - > pgd into CP0_PWBase * * We keep GPR_S0 pointing at struct kvm so we can load the ASID below . int )offsetof(struct kvm_vcpu, kvm) -int )offsetof(struct kvm_vcpu, arch), GPR_K1);struct kvm, arch.gpa_mm.pgd), GPR_S0);unsigned long )tlbmiss_handler_setup_pgd);/* delay slot */ if (cpu_has_htw)else /* Set GM bit to setup eret to VZ guest context */ 1 );1 );if (cpu_has_guestid) {/* * Set root mode GuestID , so that root TLB refill handler can * use the correct GuestID in the root TLB . /* Get current GuestID */ /* Set GuestCtl1.RID = GuestCtl1.ID */ /* GuestID handles dealiasing so we don't need to touch ASID */ goto skip_asid_restore;/* Root ASID Dealias (RAD) */ /* Save host ASID */ struct kvm_vcpu_arch, host_entryhi),/* Set the root ASID for the Guest */ struct kvm, arch.gpa_mm.context.asid));/* t1: contains the base of the ASID array, need to get the cpu id */ /* smp_processor_id */ struct thread_info, cpu), GPR_GP);/* index the ASID array */ sizeof (long )));0 , GPR_T3);#ifdef CONFIG_MIPS_ASID_BITS_VARIABLE/* * reuse ASID array offset * cpuinfo_mips is a multiple of sizeof ( long ) sizeof (struct cpuinfo_mips)/sizeof (long ));long )&cpu_data[0 ].asid_mask);long )&cpu_data[0 ].asid_mask), GPR_AT);#else #endif /* Set up KVM VZ root ASID (!guestid) */ /* Disable RDHWR access */ /* load the guest context from VCPU and return */ for (i = 1 ; i < 32 ; ++i) {/* Guest k0/k1 loaded later */ if (i == GPR_K0 || i == GPR_K1)continue ;struct kvm_vcpu_arch, gprs[i]), GPR_K1);#ifndef CONFIG_CPU_MIPSR6/* Restore hi/lo */ struct kvm_vcpu_arch, hi), GPR_K1);struct kvm_vcpu_arch, lo), GPR_K1);#endif /* Restore the guest's k0/k1 registers */ struct kvm_vcpu_arch, gprs[GPR_K0]), GPR_K1);struct kvm_vcpu_arch, gprs[GPR_K1]), GPR_K1);/* Jump to guest */ 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)struct uasm_label labels[2 ];struct uasm_reloc relocs[2 ];#ifndef CONFIG_CPU_LOONGSON64struct uasm_label *l = labels;struct uasm_reloc *r = relocs;#endif 0 , sizeof (labels));0 , sizeof (relocs));/* Save guest k1 into scratch register */ 0 ], scratch_tmp[1 ]);/* Get the VCPU pointer from the VCPU scratch register */ 0 ], scratch_vcpu[1 ]);/* Save guest k0 into VCPU structure */ struct kvm_vcpu, arch.gprs[GPR_K0]), GPR_K1);/* * Some of the common tlbex code uses current_cpu_type ( ) . For KVM we * assume symmetry and just disable preemption to silence the warning . #ifdef CONFIG_CPU_LOONGSON643 ); /* global page dir */ #ifndef __PAGETABLE_PMD_FOLDED1 ); /* middle page dir */ #endif 0 ); /* even */ 1 ); /* odd */ #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/* get pmd in GPR_K1 */ #else /* get pgd in GPR_K1 */ #endif /* we don't support huge pages yet */ #endif /* Get the VCPU pointer from the VCPU scratch register again */ 0 ], scratch_vcpu[1 ]);/* Restore the guest's k0/k1 registers */ struct kvm_vcpu, arch.gprs[GPR_K0]), GPR_K1);0 ], scratch_tmp[1 ]);/* Jump to guest */ 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)struct uasm_label labels[2 ];struct uasm_reloc relocs[2 ];struct uasm_label *l = labels;struct uasm_reloc *r = relocs;0 , sizeof (labels));0 , sizeof (relocs));/* Save guest k1 into scratch register */ 0 ], scratch_tmp[1 ]);/* Get the VCPU pointer from the VCPU scratch register */ 0 ], scratch_vcpu[1 ]);struct kvm_vcpu, arch));/* Save guest k0 into VCPU structure */ struct kvm_vcpu_arch, gprs[GPR_K0]), GPR_K1);/* Branch to the common handler */ 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)unsigned int i;struct uasm_label labels[3 ];struct uasm_reloc relocs[3 ];struct uasm_label *l = labels;struct uasm_reloc *r = relocs;0 , sizeof (labels));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 == GPR_K0 || i == GPR_K1)continue ;struct kvm_vcpu_arch, gprs[i]), GPR_K1);#ifndef CONFIG_CPU_MIPSR6/* We need to save hi/lo and restore them on the way out */ struct kvm_vcpu_arch, hi), GPR_K1);struct kvm_vcpu_arch, lo), GPR_K1);#endif /* Finally save guest k1 to VCPU */ 0 ], scratch_tmp[1 ]);struct kvm_vcpu_arch, gprs[GPR_K1]), GPR_K1);/* Now that context has been saved, we can use other registers */ /* Restore vcpu */ 0 ], scratch_vcpu[1 ]);/* * Save Host level EPC , BadVaddr and Cause to VCPU , useful to process * the exception struct kvm_vcpu_arch, pc), GPR_K1);struct kvm_vcpu_arch, host_cp0_badvaddr),struct kvm_vcpu_arch, host_cp0_cause), GPR_K1);if (cpu_has_badinstr) {struct kvm_vcpu_arch,if (cpu_has_badinstrp) {struct kvm_vcpu_arch,/* Now restore the host state just enough to run the handlers */ /* Switch EBASE to the one used by Linux */ /* load up the host EBASE */ 16 );long )&ebase);long )&ebase), GPR_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 . 16 );31 );struct kvm_vcpu_arch, fpu.fcr31),31 );if (cpu_has_msa) {/* * If MSA is enabled , save MSACSR and clear it so that later * instructions don ' t trigger MSAFPE for pending exceptions . 27 , 1 ); /* MIPS_CONF5_MSAEN */ struct kvm_vcpu_arch, fpu.msacsr),/* Restore host ASID */ if (!cpu_has_guestid) {struct kvm_vcpu_arch, host_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 struct kvm_vcpu_arch, host_pgd), GPR_K1);unsigned long )tlbmiss_handler_setup_pgd);/* delay slot */ if (cpu_has_htw)else /* Clear GM bit so we don't enter guest mode when EXL is cleared */ 1 );/* Save GuestCtl0 so we can access GExcCode after CPU migration */ struct kvm_vcpu_arch, host_cp0_guestctl0), GPR_K1);if (cpu_has_guestid) {/* * Clear root mode GuestID , so that root TLB operations use the * root GuestID in the root TLB . /* Set GuestCtl1.RID = MIPS_GCTL1_ROOT_GUESTID (i.e. 0) */ /* Now that the new EBASE has been loaded, unset BEV and KSU_USER */ 16 );#ifdef CONFIG_64BIT#endif /* Load up host GPR_GP */ struct kvm_vcpu_arch, host_gp), GPR_K1);/* Need a stack before we can jump to "C" */ struct kvm_vcpu_arch, host_stack), GPR_K1);/* Saved host state */ 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 */ /* Restore RDHWR access */ long )&hwrena);long )&hwrena), GPR_K0);/* 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 unsigned long )kvm_mips_handle_exit);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)struct uasm_label labels[2 ];struct uasm_reloc relocs[2 ];struct uasm_label *l = labels;struct uasm_reloc *r = relocs;0 , sizeof (labels));0 , sizeof (relocs));/* Return from handler Make sure interrupts are disabled */ /* * XXXKYMA : k0 / k1 could have been blown away if we processed * an exception while we were handling the exception from the * guest , reload k1 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 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)/* Put the saved pointer to vcpu (s0) back into the scratch register */ 0 ], scratch_vcpu[1 ]);/* Load up the Guest EBASE to minimize the window where BEV is set */ struct kvm_vcpu_arch, guest_ebase), GPR_K1);/* Switch EBASE back to the one used by KVM */ 16 );/* Setup status register for running guest in UM */ 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)unsigned int i;/* EBASE is already pointing to Linux */ struct kvm_vcpu_arch, host_stack), GPR_K1);int )sizeof (struct pt_regs));/* * r2 / v0 is the return code , shift it down by 2 ( arithmetic ) * to recover the err code 2 );/* Load context saved on the host stack */ for (i = 16 ; i < 31 ; ++i) {if (i == 24 )28 ;struct pt_regs, regs[i]), GPR_K1);/* Restore RDHWR access */ long )&hwrena);long )&hwrena), GPR_K0);/* Restore GPR_RA, which is the address we will return to */ struct pt_regs, regs[GPR_RA]), GPR_K1);return p;
Messung V0.5 in Prozent C=88 H=90 G=88
¤ Dauer der Verarbeitung: 0.33 Sekunden
(vorverarbeitet am 2026-09-29)
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