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

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 <redacted>
---
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

On Tue, Dec 08, 2020 at 06:57:08PM -0300, Leonardo Bras wrote:

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 <redacted>

Acked-by: Paul Mackerras <redacted>

On Tue, 8 Dec 2020 18:57:08 -0300, Leonardo Bras wrote:

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

[...]

Applied to powerpc/next.

[1/1] KVM: PPC: Book3S HV: Fix mask size for emulated msgsndp
      https://git.kernel.org/powerpc/c/87fb4978ef8f7e3d6f51ea8e259638c4e96f2fc0

cheers