diff options
| author | Simon Guo <wei.guo.simon@gmail.com> | 2018-05-23 15:02:01 +0800 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2018-06-01 10:30:10 +1000 |
| commit | 5706340a339283fe60d55ddc72ee7728a571a834 (patch) | |
| tree | 2f5c12185399ad0671cdb3baa0ca4360712aa0ab /arch/powerpc/include/asm/kvm_book3s.h | |
| parent | 533082ae86e2f1ff6cb9eca7a25202a81fc0567e (diff) | |
KVM: PPC: Book3S PR: Always fail transactions in guest privileged state
Currently the kernel doesn't use transaction memory.
And there is an issue for privileged state in the guest that:
tbegin/tsuspend/tresume/tabort TM instructions can impact MSR TM bits
without trapping into the PR host. So following code will lead to a
false mfmsr result:
tbegin <- MSR bits update to Transaction active.
beq <- failover handler branch
mfmsr <- still read MSR bits from magic page with
transaction inactive.
It is not an issue for non-privileged guest state since its mfmsr is
not patched with magic page and will always trap into the PR host.
This patch will always fail tbegin attempt for privileged state in the
guest, so that the above issue is prevented. It is benign since
currently (guest) kernel doesn't initiate a transaction.
Test case:
https://github.com/justdoitqd/publicFiles/blob/master/test_tbegin_pr.c
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/include/asm/kvm_book3s.h')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_book3s.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 43e8bb18c2d7..c1cea8222d51 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -262,9 +262,11 @@ extern void kvmppc_copy_from_svcpu(struct kvm_vcpu *vcpu); #ifdef CONFIG_PPC_TRANSACTIONAL_MEM void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu); void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu); +void kvmppc_restore_tm_sprs(struct kvm_vcpu *vcpu); #else static inline void kvmppc_save_tm_pr(struct kvm_vcpu *vcpu) {} static inline void kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu) {} +static inline void kvmppc_restore_tm_sprs(struct kvm_vcpu *vcpu) {} #endif extern int kvm_irq_bypass; |