[PATCH v2 1/1] powerpc/kvm: Fix mask size for emulated msgsndp

[Leonardo Bras]

According to ISAv3.1 and ISAv3.0b, the msgsndp is described to split RB in:
msgtype <- (RB) 32:36
payload <- (RB) 37:63
t       <- (RB) 57:63

The current way of getting 'msgtype', and 't' is missing their MSB:
msgtype: ((arg >> 27) & 0xf) : Gets (RB) 33:36, missing bit 32
t:       (arg &= 0x3f)       : Gets (RB) 58:63, missing bit 57

Fixes this by applying the correct mask.

Signed-off-by: Leonardo Bras <leobra...@gmail.com>
---
Changes since v1:
- Commit message 's/LSB/MSB/', because ISA ordering is big-endian.

 arch/powerpc/kvm/book3s_hv.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index e3b1839fc251..5af0a429cee8 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1241,9 +1241,9 @@ static int kvmppc_emulate_doorbell_instr(struct kvm_vcpu 
*vcpu)
        switch (get_xop(inst)) {
        case OP_31_XOP_MSGSNDP:
                arg = kvmppc_get_gpr(vcpu, rb);
-               if (((arg >> 27) & 0xf) != PPC_DBELL_SERVER)
+               if (((arg >> 27) & 0x1f) != PPC_DBELL_SERVER)
                        break;
-               arg &= 0x3f;
+               arg &= 0x7f;
                if (arg >= kvm->arch.emul_smt_mode)
                        break;
                tvcpu = kvmppc_find_vcpu(kvm, vcpu->vcpu_id - thr + arg);
@@ -1256,7 +1256,7 @@ static int kvmppc_emulate_doorbell_instr(struct kvm_vcpu 
*vcpu)
                break;
        case OP_31_XOP_MSGCLRP:
                arg = kvmppc_get_gpr(vcpu, rb);
-               if (((arg >> 27) & 0xf) != PPC_DBELL_SERVER)
+               if (((arg >> 27) & 0x1f) != PPC_DBELL_SERVER)
                        break;
                vcpu->arch.vcore->dpdes = 0;
                vcpu->arch.doorbell_request = 0;
-- 
2.25.4