diff options
author | Christian Borntraeger <borntraeger@de.ibm.com> | 2013-05-17 14:41:35 +0200 |
---|---|---|
committer | Gleb Natapov <gleb@redhat.com> | 2013-05-21 11:55:23 +0300 |
commit | 49b99e1e0dedbd6cc93b2d2776b60fb7151ff3d7 (patch) | |
tree | 204052379d35e6459207571b3e2bb1d460e2cef2 /arch/s390 | |
parent | 95d38fd0bcf1996082f5f8762e6f1c849755e0c6 (diff) | |
download | linux-49b99e1e0dedbd6cc93b2d2776b60fb7151ff3d7.tar.bz2 |
s390/kvm: Provide a way to prevent reentering SIE
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 <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/s390')
-rw-r--r-- | arch/s390/include/asm/kvm_host.h | 5 | ||||
-rw-r--r-- | arch/s390/kernel/asm-offsets.c | 1 | ||||
-rw-r--r-- | arch/s390/kernel/entry64.S | 4 | ||||
-rw-r--r-- | arch/s390/kvm/kvm-s390.c | 28 | ||||
-rw-r--r-- | 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 962b92e6cf00..9a809f935580 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 6456bbe1fbb1..78db6338695d 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 c2e81b4ea42c..c7daeefb9864 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 c1c7c683fa26..ef4ef21f2c73 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 efc14f687265..7a8abfd26a0f 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); |