linux-kernel - [PATCH 5.1 304/371] KVM: PPC: Book3S HV: Fix CR0 setting in TM emulation

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Date:   Wed, 24 Jul 2019 21:20:56 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Suraj Jitindar Singh <sjitindarsingh@...il.com>,
        Michael Neuling <mikey@...ling.org>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 5.1 304/371] KVM: PPC: Book3S HV: Fix CR0 setting in TM emulation

From: Michael Neuling <mikey@...ling.org>

commit 3fefd1cd95df04da67c83c1cb93b663f04b3324f upstream.

When emulating tsr, treclaim and trechkpt, we incorrectly set CR0. The
code currently sets:
    CR0 <- 00 || MSR[TS]
but according to the ISA it should be:
    CR0 <-  0 || MSR[TS] || 0

This fixes the bit shift to put the bits in the correct location.

This is a data integrity issue as CR0 is corrupted.

Fixes: 4bb3c7a0208f ("KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9")
Cc: stable@...r.kernel.org # v4.17+
Tested-by: Suraj Jitindar Singh <sjitindarsingh@...il.com>
Signed-off-by: Michael Neuling <mikey@...ling.org>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/kvm/book3s_hv_tm.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/powerpc/kvm/book3s_hv_tm.c
+++ b/arch/powerpc/kvm/book3s_hv_tm.c
@@ -131,7 +131,7 @@ int kvmhv_p9_tm_emulation(struct kvm_vcp
 		}
 		/* Set CR0 to indicate previous transactional state */
 		vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
-			(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 28);
+			(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 29);
 		/* L=1 => tresume, L=0 => tsuspend */
 		if (instr & (1 << 21)) {
 			if (MSR_TM_SUSPENDED(msr))
@@ -175,7 +175,7 @@ int kvmhv_p9_tm_emulation(struct kvm_vcp
 
 		/* Set CR0 to indicate previous transactional state */
 		vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
-			(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 28);
+			(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 29);
 		vcpu->arch.shregs.msr &= ~MSR_TS_MASK;
 		return RESUME_GUEST;
 
@@ -205,7 +205,7 @@ int kvmhv_p9_tm_emulation(struct kvm_vcp
 
 		/* Set CR0 to indicate previous transactional state */
 		vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
-			(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 28);
+			(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 29);
 		vcpu->arch.shregs.msr = msr | MSR_TS_S;
 		return RESUME_GUEST;
 	}