diff options
| author | Paul Mackerras | 2013-08-06 14:15:19 +1000 |
|---|---|---|
| committer | Alexander Graf | 2013-08-28 16:47:49 +0200 |
| commit | 8b23de29489fd63fce753db9d53055e4bbf8f616 (patch) | |
| tree | 94e266d8d7029bbb411568454d0c4df56b52d5fd /arch/powerpc/kvm/book3s_pr.c | |
| parent | 9d1ffdd8f34b1f89264effd10e75ea4d6272690e (diff) | |
KVM: PPC: Book3S PR: Make instruction fetch fallback work for system calls
It turns out that if we exit the guest due to a hcall instruction (sc 1),
and the loading of the instruction in the guest exit path fails for any
reason, the call to kvmppc_ld() in kvmppc_get_last_inst() fetches the
instruction after the hcall instruction rather than the hcall itself.
This in turn means that the instruction doesn't get recognized as an
hcall in kvmppc_handle_exit_pr() but gets passed to the guest kernel
as a sc instruction. That usually results in the guest kernel getting
a return code of 38 (ENOSYS) from an hcall, which often triggers a
BUG_ON() or other failure.
This fixes the problem by adding a new variant of kvmppc_get_last_inst()
called kvmppc_get_last_sc(), which fetches the instruction if necessary
from pc - 4 rather than pc.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch/powerpc/kvm/book3s_pr.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_pr.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 983e5eda892f..27db1e665959 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -792,7 +792,7 @@ program_interrupt: } case BOOK3S_INTERRUPT_SYSCALL: if (vcpu->arch.papr_enabled && - (kvmppc_get_last_inst(vcpu) == 0x44000022) && + (kvmppc_get_last_sc(vcpu) == 0x44000022) && !(vcpu->arch.shared->msr & MSR_PR)) { /* SC 1 papr hypercalls */ ulong cmd = kvmppc_get_gpr(vcpu, 3); |