From: Jonathan Cameron <jonathan.cameron@huawei.com>
To: Sascha Bischoff <Sascha.Bischoff@arm.com>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"kvmarm@lists.linux.dev" <kvmarm@lists.linux.dev>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>, nd <nd@arm.com>,
"maz@kernel.org" <maz@kernel.org>,
"oliver.upton@linux.dev" <oliver.upton@linux.dev>,
Joey Gouly <Joey.Gouly@arm.com>,
Suzuki Poulose <Suzuki.Poulose@arm.com>,
"yuzenghui@huawei.com" <yuzenghui@huawei.com>,
"peter.maydell@linaro.org" <peter.maydell@linaro.org>,
"lpieralisi@kernel.org" <lpieralisi@kernel.org>,
Timothy Hayes <Timothy.Hayes@arm.com>
Subject: Re: [PATCH v6 14/39] KVM: arm64: gic-v5: Trap and emulate ICC_IDR0_EL1 accesses
Date: Thu, 19 Mar 2026 10:38:26 +0000 [thread overview]
Message-ID: <20260319103826.00004be1@huawei.com> (raw)
In-Reply-To: <20260317113949.2548118-15-sascha.bischoff@arm.com>
On Tue, 17 Mar 2026 11:43:34 +0000
Sascha Bischoff <Sascha.Bischoff@arm.com> wrote:
> Unless accesses to the ICC_IDR0_EL1 are trapped by KVM, the guest
> reads the same state as the host. This isn't desirable as it limits
> the migratability of VMs and means that KVM can't hide hardware
> features such as FEAT_GCIE_LEGACY.
>
> Trap and emulate accesses to the register, and present KVM's chosen ID
> bits and Priority bits (which is 5, as GICv5 only supports 5 bits of
> priority in the CPU interface). FEAT_GCIE_LEGACY is never presented to
> the guest as it is only relevant for nested guests doing mixed GICv5
> and GICv3 support.
>
> Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Does what I'd expect.
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
next prev parent reply other threads:[~2026-03-19 10:38 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-17 11:39 [PATCH v6 00/39] KVM: arm64: Introduce vGIC-v5 with PPI support Sascha Bischoff
2026-03-17 11:40 ` [PATCH v6 01/39] KVM: arm64: vgic-v3: Drop userspace write sanitization for ID_AA64PFR0.GIC on GICv5 Sascha Bischoff
2026-03-19 10:02 ` Jonathan Cameron
2026-03-19 11:35 ` Sascha Bischoff
2026-03-20 10:27 ` Jonathan Cameron
2026-03-17 11:40 ` [PATCH v6 02/39] KVM: arm64: vgic: Rework vgic_is_v3() and add vgic_host_has_gicvX() Sascha Bischoff
2026-03-17 11:40 ` [PATCH v6 03/39] KVM: arm64: Return early from kvm_finalize_sys_regs() if guest has run Sascha Bischoff
2026-03-19 10:12 ` Jonathan Cameron
2026-03-19 11:41 ` Sascha Bischoff
2026-03-17 11:40 ` [PATCH v6 04/39] KVM: arm64: vgic: Split out mapping IRQs and setting irq_ops Sascha Bischoff
2026-03-17 16:00 ` Marc Zyngier
2026-03-18 17:30 ` Sascha Bischoff
2026-03-17 11:41 ` [PATCH v6 05/39] arm64/sysreg: Add remaining GICv5 ICC_ & ICH_ sysregs for KVM support Sascha Bischoff
2026-03-17 11:41 ` [PATCH v6 06/39] arm64/sysreg: Add GICR CDNMIA encoding Sascha Bischoff
2026-03-17 11:41 ` [PATCH v6 07/39] KVM: arm64: gic-v5: Add ARM_VGIC_V5 device to KVM headers Sascha Bischoff
2026-03-17 11:42 ` [PATCH v6 08/39] KVM: arm64: gic: Introduce interrupt type helpers Sascha Bischoff
2026-03-17 11:42 ` [PATCH v6 09/39] KVM: arm64: gic-v5: Add Arm copyright header Sascha Bischoff
2026-03-17 11:42 ` [PATCH v6 10/39] KVM: arm64: gic-v5: Detect implemented PPIs on boot Sascha Bischoff
2026-03-17 11:42 ` [PATCH v6 11/39] KVM: arm64: gic-v5: Sanitize ID_AA64PFR2_EL1.GCIE Sascha Bischoff
2026-03-19 10:31 ` Jonathan Cameron
2026-03-19 14:02 ` Sascha Bischoff
2026-03-17 11:43 ` [PATCH v6 12/39] KVM: arm64: gic-v5: Support GICv5 FGTs & FGUs Sascha Bischoff
2026-03-17 11:43 ` [PATCH v6 13/39] KVM: arm64: gic-v5: Add emulation for ICC_IAFFIDR_EL1 accesses Sascha Bischoff
2026-03-19 10:34 ` Jonathan Cameron
2026-03-17 11:43 ` [PATCH v6 14/39] KVM: arm64: gic-v5: Trap and emulate ICC_IDR0_EL1 accesses Sascha Bischoff
2026-03-19 10:38 ` Jonathan Cameron [this message]
2026-03-17 11:43 ` [PATCH v6 15/39] KVM: arm64: gic-v5: Add vgic-v5 save/restore hyp interface Sascha Bischoff
2026-03-17 11:44 ` [PATCH v6 16/39] KVM: arm64: gic-v5: Implement GICv5 load/put and save/restore Sascha Bischoff
2026-03-17 11:44 ` [PATCH v6 17/39] KVM: arm64: gic-v5: Finalize GICv5 PPIs and generate mask Sascha Bischoff
2026-03-17 11:44 ` [PATCH v6 18/39] KVM: arm64: gic: Introduce queue_irq_unlock to irq_ops Sascha Bischoff
2026-03-17 11:44 ` [PATCH v6 19/39] KVM: arm64: gic-v5: Implement PPI interrupt injection Sascha Bischoff
2026-03-17 16:31 ` Marc Zyngier
2026-03-18 17:31 ` Sascha Bischoff
2026-03-17 11:45 ` [PATCH v6 20/39] KVM: arm64: gic-v5: Init Private IRQs (PPIs) for GICv5 Sascha Bischoff
2026-03-17 16:42 ` Marc Zyngier
2026-03-18 17:34 ` Sascha Bischoff
2026-03-17 11:45 ` [PATCH v6 21/39] KVM: arm64: gic-v5: Clear TWI if single task running Sascha Bischoff
2026-03-17 11:45 ` [PATCH v6 22/39] KVM: arm64: gic-v5: Check for pending PPIs Sascha Bischoff
2026-03-17 17:08 ` Marc Zyngier
2026-03-19 8:27 ` Sascha Bischoff
2026-03-17 11:45 ` [PATCH v6 23/39] KVM: arm64: gic-v5: Trap and mask guest ICC_PPI_ENABLERx_EL1 writes Sascha Bischoff
2026-03-17 11:46 ` [PATCH v6 24/39] KVM: arm64: Introduce set_direct_injection irq_op Sascha Bischoff
2026-03-17 11:46 ` [PATCH v6 25/39] KVM: arm64: gic-v5: Implement direct injection of PPIs Sascha Bischoff
2026-03-17 11:46 ` [PATCH v6 26/39] KVM: arm64: gic-v5: Support GICv5 interrupts with KVM_IRQ_LINE Sascha Bischoff
2026-03-17 11:46 ` [PATCH v6 27/39] KVM: arm64: gic-v5: Create and initialise vgic_v5 Sascha Bischoff
2026-03-17 11:47 ` [PATCH v6 28/39] KVM: arm64: gic-v5: Initialise ID and priority bits when resetting vcpu Sascha Bischoff
2026-03-17 11:47 ` [PATCH v6 29/39] KVM: arm64: gic-v5: Enlighten arch timer for GICv5 Sascha Bischoff
2026-03-17 18:05 ` Marc Zyngier
2026-03-19 8:59 ` Sascha Bischoff
2026-03-17 11:47 ` [PATCH v6 30/39] KVM: arm64: gic-v5: Mandate architected PPI for PMU emulation on GICv5 Sascha Bischoff
2026-03-17 11:48 ` [PATCH v6 31/39] KVM: arm64: gic: Hide GICv5 for protected guests Sascha Bischoff
2026-03-17 11:48 ` [PATCH v6 32/39] KVM: arm64: gic-v5: Hide FEAT_GCIE from NV GICv5 guests Sascha Bischoff
2026-03-17 11:48 ` [PATCH v6 33/39] KVM: arm64: gic-v5: Introduce kvm_arm_vgic_v5_ops and register them Sascha Bischoff
2026-03-17 11:48 ` [PATCH v6 34/39] KVM: arm64: gic-v5: Set ICH_VCTLR_EL2.En on boot Sascha Bischoff
2026-03-17 11:49 ` [PATCH v6 35/39] KVM: arm64: gic-v5: Probe for GICv5 device Sascha Bischoff
2026-03-18 15:34 ` Joey Gouly
2026-03-19 8:36 ` Sascha Bischoff
2026-03-17 11:49 ` [PATCH v6 36/39] Documentation: KVM: Introduce documentation for VGICv5 Sascha Bischoff
2026-03-17 11:49 ` [PATCH v6 37/39] KVM: arm64: gic-v5: Communicate userspace-driveable PPIs via a UAPI Sascha Bischoff
2026-03-17 11:49 ` [PATCH v6 38/39] KVM: arm64: selftests: Introduce a minimal GICv5 PPI selftest Sascha Bischoff
2026-03-17 11:50 ` [PATCH v6 39/39] KVM: arm64: selftests: Add no-vgic-v5 selftest Sascha Bischoff
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