From: Anshuman Khandual <anshuman.khandual@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual <anshuman.khandual@arm.com>, Jonathan Corbet <corbet@lwn.net>, Marc Zyngier <maz@kernel.org>, Oliver Upton <oliver.upton@linux.dev>, James Morse <james.morse@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Brown <broonie@kernel.org>, Mark Rutland <mark.rutland@arm.com>, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [RFC 5/8] KVM: arm64: Explicitly handle MDSELR_EL1 traps as UNDEFINED Date: Fri, 5 Apr 2024 13:30:05 +0530 [thread overview] Message-ID: <20240405080008.1225223-6-anshuman.khandual@arm.com> (raw) In-Reply-To: <20240405080008.1225223-1-anshuman.khandual@arm.com> Currently read_sanitised_id_aa64dfr0_el1() caps the ID_AA64DFR0.DebugVer to ID_AA64DFR0_DebugVer_V8P8, resulting in FEAT_Debugv8p9 not being exposed to the guest. MDSELR_EL1 register access in the guest, is currently trapped by the existing configuration of the fine-grained traps. As the register is not described in sys_reg_descs[] table emulate_sys_reg() will warn that this is unknown access before injecting an UNDEFINED exception into the guest. Any well-behaved guests shouldn't try to use this register, but any badly-behaved guests could, thus resulting in unnecessary warnings. To avoid such warnings, access to MDSELR_EL1 should be explicitly handled as UNDEFINED via updating sys_reg_desc[] as required. Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.linux.dev Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- arch/arm64/kvm/sys_regs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c9f4f387155f..2956bdcd358e 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2203,6 +2203,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_MDSCR_EL1), trap_debug_regs, reset_val, MDSCR_EL1, 0 }, DBG_BCR_BVR_WCR_WVR_EL1(2), DBG_BCR_BVR_WCR_WVR_EL1(3), + { SYS_DESC(SYS_MDSELR_EL1), undef_access }, DBG_BCR_BVR_WCR_WVR_EL1(4), DBG_BCR_BVR_WCR_WVR_EL1(5), DBG_BCR_BVR_WCR_WVR_EL1(6), -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Anshuman Khandual <anshuman.khandual@arm.com> To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual <anshuman.khandual@arm.com>, Jonathan Corbet <corbet@lwn.net>, Marc Zyngier <maz@kernel.org>, Oliver Upton <oliver.upton@linux.dev>, James Morse <james.morse@arm.com>, Suzuki K Poulose <suzuki.poulose@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Brown <broonie@kernel.org>, Mark Rutland <mark.rutland@arm.com>, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [RFC 5/8] KVM: arm64: Explicitly handle MDSELR_EL1 traps as UNDEFINED Date: Fri, 5 Apr 2024 13:30:05 +0530 [thread overview] Message-ID: <20240405080008.1225223-6-anshuman.khandual@arm.com> (raw) In-Reply-To: <20240405080008.1225223-1-anshuman.khandual@arm.com> Currently read_sanitised_id_aa64dfr0_el1() caps the ID_AA64DFR0.DebugVer to ID_AA64DFR0_DebugVer_V8P8, resulting in FEAT_Debugv8p9 not being exposed to the guest. MDSELR_EL1 register access in the guest, is currently trapped by the existing configuration of the fine-grained traps. As the register is not described in sys_reg_descs[] table emulate_sys_reg() will warn that this is unknown access before injecting an UNDEFINED exception into the guest. Any well-behaved guests shouldn't try to use this register, but any badly-behaved guests could, thus resulting in unnecessary warnings. To avoid such warnings, access to MDSELR_EL1 should be explicitly handled as UNDEFINED via updating sys_reg_desc[] as required. Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.linux.dev Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- arch/arm64/kvm/sys_regs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c9f4f387155f..2956bdcd358e 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2203,6 +2203,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_MDSCR_EL1), trap_debug_regs, reset_val, MDSCR_EL1, 0 }, DBG_BCR_BVR_WCR_WVR_EL1(2), DBG_BCR_BVR_WCR_WVR_EL1(3), + { SYS_DESC(SYS_MDSELR_EL1), undef_access }, DBG_BCR_BVR_WCR_WVR_EL1(4), DBG_BCR_BVR_WCR_WVR_EL1(5), DBG_BCR_BVR_WCR_WVR_EL1(6), -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2024-04-05 8:00 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-04-05 8:00 [RFC 0/8] arm64/hw_breakpoint: Enable FEAT_Debugv8p9 Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 8:00 ` [RFC 1/8] arm64/sysreg: Add register fields for MDSELR_EL1 Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 12:52 ` Mark Brown 2024-04-05 12:52 ` Mark Brown 2024-04-05 8:00 ` [RFC 2/8] arm64/sysreg: Add register fields for HDFGRTR2_EL2 Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 12:59 ` Mark Brown 2024-04-05 12:59 ` Mark Brown 2024-04-05 8:00 ` [RFC 3/8] arm64/sysreg: Add register fields for HDFGWTR2_EL2 Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 13:08 ` Mark Brown 2024-04-05 13:08 ` Mark Brown 2024-04-05 8:00 ` [RFC 4/8] arm64/sysreg: Update ID_AA64MMFR0_EL1 register Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 13:16 ` Mark Brown 2024-04-05 13:16 ` Mark Brown 2024-04-05 8:00 ` Anshuman Khandual [this message] 2024-04-05 8:00 ` [RFC 5/8] KVM: arm64: Explicitly handle MDSELR_EL1 traps as UNDEFINED Anshuman Khandual 2024-04-05 10:15 ` Marc Zyngier 2024-04-05 10:15 ` Marc Zyngier 2024-04-12 2:41 ` Anshuman Khandual 2024-04-12 2:41 ` Anshuman Khandual 2024-04-12 11:05 ` Marc Zyngier 2024-04-12 11:05 ` Marc Zyngier 2024-04-16 5:46 ` Anshuman Khandual 2024-04-16 5:46 ` Anshuman Khandual 2024-04-16 8:15 ` Marc Zyngier 2024-04-16 8:15 ` Marc Zyngier 2024-04-05 8:00 ` [RFC 6/8] arm64/cpufeature: Add field details for ID_AA64DFR1_EL1 register Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 8:00 ` [RFC 7/8] arm64/boot: Enable EL2 requirements for FEAT_Debugv8p9 Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 8:00 ` [RFC 8/8] arm64/hw_breakpoint: Enable FEAT_Debugv8p9 Anshuman Khandual 2024-04-05 8:00 ` Anshuman Khandual 2024-04-05 10:26 ` Marc Zyngier 2024-04-05 10:26 ` Marc Zyngier 2024-04-16 3:13 ` Anshuman Khandual 2024-04-16 3:13 ` Anshuman Khandual 2024-04-16 3:54 ` [RFC 0/8] " Anshuman Khandual 2024-04-16 3:54 ` Anshuman Khandual
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