From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Borntraeger Subject: [PATCH 5/8] s390/kvm: Provide a way to prevent reentering SIE Date: Fri, 17 May 2013 14:41:35 +0200 Message-ID: <1368794498-2051-6-git-send-email-borntraeger@de.ibm.com> References: <1368794498-2051-1-git-send-email-borntraeger@de.ibm.com> Return-path: In-Reply-To: <1368794498-2051-1-git-send-email-borntraeger@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: Marcelo Tossati , Gleb Natapov , Paolo Bonzini Cc: Cornelia Huck , Heiko Carstens , Martin Schwidefsky , KVM , linux-s390 , Christian Borntraeger List-ID: Lets provide functions to prevent KVM from reentering SIE and to kick cpus out of SIE. We cannot use the common kvm_vcpu_kick code, since we need to kick out guests in places that hold architecture specific locks (e.g. pgste lock) which might be necessary on the other cpus - so no waiting possible. So lets provide a bit in a private field of the sie control block that acts as a gate keeper, after we claimed we are in SIE. Please note that we do not reuse prog0c, since we want to access that bit without atomic ops. Signed-off-by: Christian Borntraeger Acked-by: Martin Schwidefsky --- arch/s390/include/asm/kvm_host.h | 5 ++++- arch/s390/kernel/asm-offsets.c | 1 + arch/s390/kernel/entry64.S | 4 +++- arch/s390/kvm/kvm-s390.c | 28 ++++++++++++++++++++++++++++ arch/s390/kvm/kvm-s390.h | 4 ++++ 5 files changed, 40 insertions(+), 2 deletions(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 962b92e..9a809f9 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -71,7 +71,10 @@ struct kvm_s390_sie_block { __u8 reserved08[4]; /* 0x0008 */ #define PROG_IN_SIE (1<<0) __u32 prog0c; /* 0x000c */ - __u8 reserved10[24]; /* 0x0010 */ + __u8 reserved10[16]; /* 0x0010 */ +#define PROG_BLOCK_SIE 0x00000001 + atomic_t prog20; /* 0x0020 */ + __u8 reserved24[4]; /* 0x0024 */ __u64 cputm; /* 0x0028 */ __u64 ckc; /* 0x0030 */ __u64 epoch; /* 0x0038 */ diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index 6456bbe..78db633 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -163,6 +163,7 @@ int main(void) DEFINE(__THREAD_trap_tdb, offsetof(struct task_struct, thread.trap_tdb)); DEFINE(__GMAP_ASCE, offsetof(struct gmap, asce)); DEFINE(__SIE_PROG0C, offsetof(struct kvm_s390_sie_block, prog0c)); + DEFINE(__SIE_PROG20, offsetof(struct kvm_s390_sie_block, prog20)); #endif /* CONFIG_32BIT */ return 0; } diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S index c2e81b4..c7daeef 100644 --- a/arch/s390/kernel/entry64.S +++ b/arch/s390/kernel/entry64.S @@ -958,7 +958,9 @@ sie_loop: lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce sie_gmap: lg %r14,__SF_EMPTY(%r15) # get control block pointer - oi __SIE_PROG0C+3(%r14),1 # we are in SIE now + oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now + tm __SIE_PROG20+3(%r14),1 # last exit... + jnz sie_done LPP __SF_EMPTY(%r15) # set guest id sie 0(%r14) sie_done: diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index c1c7c68..ef4ef21 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -454,6 +454,34 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) return 0; } +void s390_vcpu_block(struct kvm_vcpu *vcpu) +{ + atomic_set_mask(PROG_BLOCK_SIE, &vcpu->arch.sie_block->prog20); +} + +void s390_vcpu_unblock(struct kvm_vcpu *vcpu) +{ + atomic_clear_mask(PROG_BLOCK_SIE, &vcpu->arch.sie_block->prog20); +} + +/* + * Kick a guest cpu out of SIE and wait until SIE is not running. + * If the CPU is not running (e.g. waiting as idle) the function will + * return immediately. */ +void exit_sie(struct kvm_vcpu *vcpu) +{ + atomic_set_mask(CPUSTAT_STOP_INT, &vcpu->arch.sie_block->cpuflags); + while (vcpu->arch.sie_block->prog0c & PROG_IN_SIE) + cpu_relax(); +} + +/* Kick a guest cpu out of SIE and prevent SIE-reentry */ +void exit_sie_sync(struct kvm_vcpu *vcpu) +{ + s390_vcpu_block(vcpu); + exit_sie(vcpu); +} + int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { /* kvm common code refers to this, but never calls it */ diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index efc14f6..7a8abfd 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -133,6 +133,10 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu); /* implemented in kvm-s390.c */ int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr); +void s390_vcpu_block(struct kvm_vcpu *vcpu); +void s390_vcpu_unblock(struct kvm_vcpu *vcpu); +void exit_sie(struct kvm_vcpu *vcpu); +void exit_sie_sync(struct kvm_vcpu *vcpu); /* implemented in diag.c */ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu); -- 1.8.1.4