From: Martin Schwidefsky Date: Fri, 17 May 2013 12:41:37 +0000 (+0200) Subject: s390/kvm: avoid automatic sie reentry X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7c470539c95630c1f2a10f109e96f249730b75eb;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git s390/kvm: avoid automatic sie reentry Do not automatically restart the sie instruction in entry64.S after an interrupt, return to the caller with a reason code instead. That allows to deal with RCU and other conditions in C code. Signed-off-by: Martin Schwidefsky Signed-off-by: Christian Borntraeger Signed-off-by: Gleb Natapov --- diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S index c7daeefb9864..51d99acc16fd 100644 --- a/arch/s390/kernel/entry64.S +++ b/arch/s390/kernel/entry64.S @@ -47,7 +47,6 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \ _TIF_MCCK_PENDING) _TIF_TRACE = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \ _TIF_SYSCALL_TRACEPOINT) -_TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING) #define BASED(name) name-system_call(%r13) @@ -81,25 +80,27 @@ _TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING) #endif .endm - .macro HANDLE_SIE_INTERCEPT scratch,pgmcheck + .macro HANDLE_SIE_INTERCEPT scratch,reason #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE) tmhh %r8,0x0001 # interrupting from user ? - jnz .+52 + jnz .+62 lgr \scratch,%r9 - slg \scratch,BASED(.Lsie_loop) - clg \scratch,BASED(.Lsie_length) - .if \pgmcheck + slg \scratch,BASED(.Lsie_critical) + clg \scratch,BASED(.Lsie_critical_length) + .if \reason==1 # Some program interrupts are suppressing (e.g. protection). # We must also check the instruction after SIE in that case. # do_protection_exception will rewind to rewind_pad - jh .+32 + jh .+42 .else - jhe .+32 + jhe .+42 .endif - lg %r9,BASED(.Lsie_loop) - LPP BASED(.Lhost_id) # set host id - lg %r14,__SF_EMPTY(%r15) # get control block pointer + lg %r14,__SF_EMPTY(%r15) # get control block pointer + LPP __SF_EMPTY+16(%r15) # set host id ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE + lctlg %c1,%c1,__LC_USER_ASCE # load primary asce + larl %r9,sie_exit # skip forward to sie_exit + mvi __SF_EMPTY+31(%r15),\reason # set exit reason #endif .endm @@ -452,7 +453,7 @@ ENTRY(io_int_handler) lg %r12,__LC_THREAD_INFO larl %r13,system_call lmg %r8,%r9,__LC_IO_OLD_PSW - HANDLE_SIE_INTERCEPT %r14,0 + HANDLE_SIE_INTERCEPT %r14,2 SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT tmhh %r8,0x0001 # interrupting from user? jz io_skip @@ -597,7 +598,7 @@ ENTRY(ext_int_handler) lg %r12,__LC_THREAD_INFO larl %r13,system_call lmg %r8,%r9,__LC_EXT_OLD_PSW - HANDLE_SIE_INTERCEPT %r14,0 + HANDLE_SIE_INTERCEPT %r14,3 SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_STACK,STACK_SHIFT tmhh %r8,0x0001 # interrupting from user ? jz ext_skip @@ -645,7 +646,7 @@ ENTRY(mcck_int_handler) lg %r12,__LC_THREAD_INFO larl %r13,system_call lmg %r8,%r9,__LC_MCK_OLD_PSW - HANDLE_SIE_INTERCEPT %r14,0 + HANDLE_SIE_INTERCEPT %r14,4 tm __LC_MCCK_CODE,0x80 # system damage? jo mcck_panic # yes -> rest of mcck code invalid lghi %r14,__LC_CPU_TIMER_SAVE_AREA @@ -939,19 +940,8 @@ ENTRY(sie64a) stmg %r6,%r14,__SF_GPRS(%r15) # save kernel registers stg %r2,__SF_EMPTY(%r15) # save control block pointer stg %r3,__SF_EMPTY+8(%r15) # save guest register save area - xc __SF_EMPTY+16(8,%r15),__SF_EMPTY+16(%r15) # host id == 0 + xc __SF_EMPTY+16(16,%r15),__SF_EMPTY+16(%r15) # host id & reason lmg %r0,%r13,0(%r3) # load guest gprs 0-13 -# some program checks are suppressing. C code (e.g. do_protection_exception) -# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other -# instructions in the sie_loop should not cause program interrupts. So -# lets use a nop (47 00 00 00) as a landing pad. -# See also HANDLE_SIE_INTERCEPT -rewind_pad: - nop 0 -sie_loop: - lg %r14,__LC_THREAD_INFO # pointer thread_info struct - tm __TI_flags+7(%r14),_TIF_EXIT_SIE - jnz sie_exit lg %r14,__LC_GMAP # get gmap pointer ltgr %r14,%r14 jz sie_gmap @@ -966,33 +956,33 @@ sie_gmap: sie_done: LPP __SF_EMPTY+16(%r15) # set host id ni __SIE_PROG0C+3(%r14),0xfe # no longer in SIE - lg %r14,__LC_THREAD_INFO # pointer thread_info struct -sie_exit: lctlg %c1,%c1,__LC_USER_ASCE # load primary asce +# some program checks are suppressing. C code (e.g. do_protection_exception) +# will rewind the PSW by the ILC, which is 4 bytes in case of SIE. Other +# instructions beween sie64a and sie_done should not cause program +# interrupts. So lets use a nop (47 00 00 00) as a landing pad. +# See also HANDLE_SIE_INTERCEPT +rewind_pad: + nop 0 +sie_exit: lg %r14,__SF_EMPTY+8(%r15) # load guest register save area stmg %r0,%r13,0(%r14) # save guest gprs 0-13 lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers - lghi %r2,0 + lg %r2,__SF_EMPTY+24(%r15) # return exit reason code br %r14 sie_fault: - lctlg %c1,%c1,__LC_USER_ASCE # load primary asce - lg %r14,__LC_THREAD_INFO # pointer thread_info struct - lg %r14,__SF_EMPTY+8(%r15) # load guest register save area - stmg %r0,%r13,0(%r14) # save guest gprs 0-13 - lmg %r6,%r14,__SF_GPRS(%r15) # restore kernel registers - lghi %r2,-EFAULT - br %r14 + lghi %r14,-EFAULT + stg %r14,__SF_EMPTY+24(%r15) # set exit reason code + j sie_exit .align 8 -.Lsie_loop: - .quad sie_loop -.Lsie_length: - .quad sie_done - sie_loop -.Lhost_id: - .quad 0 +.Lsie_critical: + .quad sie_gmap +.Lsie_critical_length: + .quad sie_done - sie_gmap EX_TABLE(rewind_pad,sie_fault) - EX_TABLE(sie_loop,sie_fault) + EX_TABLE(sie_exit,sie_fault) #endif .section .rodata, "a" diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 08227c1e816f..93444c4dae5a 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -707,7 +707,9 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) trace_kvm_s390_sie_enter(vcpu, atomic_read(&vcpu->arch.sie_block->cpuflags)); rc = sie64a(vcpu->arch.sie_block, vcpu->run->s.regs.gprs); - if (rc) { + if (rc > 0) + rc = 0; + if (rc < 0) { if (kvm_is_ucontrol(vcpu->kvm)) { rc = SIE_INTERCEPT_UCONTROL; } else {