On 07/20/2018 09:10 AM, Janosch Frank wrote:
Let's introduce an explicit check if skeys have already been enabled
for the vcpu, so we don't have to check the mm context if we don't
have the storage key facility. >
This let's us check for enablement without having to take the mm
semaphore and thus speedup skey emulation.
Didn't the existing if statement already prevent going into the
s390_enable_skey function?
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 1 +
arch/s390/kvm/priv.c | 5 ++---
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a2188e309bd6..2916f0a5585c 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -655,6 +655,7 @@ struct kvm_vcpu_arch {
seqcount_t cputm_seqcount;
__u64 cputm_start;
bool gs_enabled;
+ bool skey_enabled;
};
struct kvm_vm_stat {
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 83c678266588..e78c381c8a24 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -209,9 +209,7 @@ int kvm_s390_skey_check_enable(struct kvm_vcpu *vcpu)
trace_kvm_s390_skey_related_inst(vcpu);
/* Already enabled? */
- if (vcpu->kvm->arch.use_skf &&
- !(sie_block->ictl & (ICTL_ISKE | ICTL_SSKE | ICTL_RRBE)) &&
- !kvm_s390_test_cpuflags(vcpu, CPUSTAT_KSS))
+ if (vcpu->arch.skey_enabled)
return 0;
rc = s390_enable_skey();
@@ -225,6 +223,7 @@ int kvm_s390_skey_check_enable(struct kvm_vcpu *vcpu)
sie_block->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
else
sie_block->ictl &= ~(ICTL_ISKE | ICTL_SSKE | ICTL_RRBE);
+ vcpu->arch.skey_enabled = true;
return 0;
}
Now we have 2 variables for skeys (use_skf and skey_enabled), shouldn't
we combine them into one struct? I feel it would be easier to understand
the code.
Thanks
Farhan
