2020-12-08 22:01:25

by Leonardo Brás

Subject: [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 <[email protected]>
---
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

2020-12-15 02:47:00

by Paul Mackerras

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

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 <[email protected]>

Acked-by: Paul Mackerras <[email protected]>

2020-12-21 11:05:05

by Michael Ellerman

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

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