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From: James Clark <james.clark@arm.com>
To: kvmarm@lists.linux.dev
Cc: James Clark <james.clark@arm.com>, Marc Zyngier <maz@kernel.org>,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] KVM: arm64: PMU: Fix PMCR_EL0 reset value
Date: Fri,  9 Dec 2022 16:44:46 +0000	[thread overview]
Message-ID: <20221209164446.1972014-2-james.clark@arm.com> (raw)
In-Reply-To: <20221209164446.1972014-1-james.clark@arm.com>

ARMV8_PMU_PMCR_N_MASK is an unshifted value which results in the wrong
reset value for PMCR_EL0, so shift it to fix it.

This fixes the following error when running qemu:

  $ qemu-system-aarch64 -cpu host -machine type=virt,accel=kvm -kernel ...

  target/arm/helper.c:1813: pmevcntr_rawwrite: Assertion `counter < pmu_num_counters(env)' failed.

Fixes: 292e8f149476 ("KVM: arm64: PMU: Simplify PMCR_EL0 reset handling")
Signed-off-by: James Clark <james.clark@arm.com>
---
 arch/arm64/kvm/sys_regs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d5ee52d6bf73..c6cbfe6b854b 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -646,7 +646,7 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 		return;
 
 	/* Only preserve PMCR_EL0.N, and reset the rest to 0 */
-	pmcr = read_sysreg(pmcr_el0) & ARMV8_PMU_PMCR_N_MASK;
+	pmcr = read_sysreg(pmcr_el0) & (ARMV8_PMU_PMCR_N_MASK << ARMV8_PMU_PMCR_N_SHIFT);
 	if (!kvm_supports_32bit_el0())
 		pmcr |= ARMV8_PMU_PMCR_LC;
 
-- 
2.25.1


  reply	other threads:[~2022-12-09 16:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-09 16:44 [PATCH 0/1] KVM: arm64: PMU: Fix PMCR_EL0 reset value James Clark
2022-12-09 16:44 ` James Clark [this message]
2022-12-09 17:58   ` [PATCH 1/1] " Oliver Upton
2022-12-10 11:16     ` Marc Zyngier
2022-12-12  6:08     ` Anshuman Khandual
2022-12-13 18:22     ` Ricardo Koller
2022-12-12  9:08 ` [PATCH 0/1] " Marc Zyngier
2023-01-03 17:57 ` Marc Zyngier

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