From: Marc Zyngier <maz@kernel.org>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Alexander Graf <graf@amazon.com>,
Andrew Jones <drjones@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Eric Auger <eric.auger@redhat.com>,
Heinrich Schuchardt <xypron.glpk@gmx.de>,
Julien Grall <julien.grall@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Steven Price <steven.price@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Zenghui Yu <yuzenghui@huawei.com>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
kvmarm@lists.cs.columbia.edu
Subject: [PATCH 15/22] KVM: arm64: Don't set HCR_EL2.TVM when S2FWB is supported
Date: Wed, 20 Nov 2019 16:42:29 +0000 [thread overview]
Message-ID: <20191120164236.29359-16-maz@kernel.org> (raw)
In-Reply-To: <20191120164236.29359-1-maz@kernel.org>
From: Christoffer Dall <christoffer.dall@arm.com>
On CPUs that support S2FWB (Armv8.4+), KVM configures the stage 2 page
tables to override the memory attributes of memory accesses, regardless
of the stage 1 page table configurations, and also when the stage 1 MMU
is turned off. This results in all memory accesses to RAM being
cacheable, including during early boot of the guest.
On CPUs without this feature, memory accesses were non-cacheable during
boot until the guest turned on the stage 1 MMU, and we had to detect
when the guest turned on the MMU, such that we could invalidate all cache
entries and ensure a consistent view of memory with the MMU turned on.
When the guest turned on the caches, we would call stage2_flush_vm()
from kvm_toggle_cache().
However, stage2_flush_vm() walks all the stage 2 tables, and calls
__kvm_flush-dcache_pte, which on a system with S2FWB does ... absolutely
nothing.
We can avoid that whole song and dance, and simply not set TVM when
creating a VM on a system that has S2FWB.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20191028130541.30536-1-christoffer.dall@arm.com
---
arch/arm64/include/asm/kvm_arm.h | 3 +--
arch/arm64/include/asm/kvm_emulate.h | 12 +++++++++++-
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index ddf9d762ac62..6e5d839f42b5 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -61,7 +61,6 @@
* RW: 64bit by default, can be overridden for 32bit VMs
* TAC: Trap ACTLR
* TSC: Trap SMC
- * TVM: Trap VM ops (until M+C set in SCTLR_EL1)
* TSW: Trap cache operations by set/way
* TWE: Trap WFE
* TWI: Trap WFI
@@ -74,7 +73,7 @@
* SWIO: Turn set/way invalidates into set/way clean+invalidate
*/
#define HCR_GUEST_FLAGS (HCR_TSC | HCR_TSW | HCR_TWE | HCR_TWI | HCR_VM | \
- HCR_TVM | HCR_BSU_IS | HCR_FB | HCR_TAC | \
+ HCR_BSU_IS | HCR_FB | HCR_TAC | \
HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \
HCR_FMO | HCR_IMO)
#define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index d69c1efc63e7..6e92f6c7b1e4 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -53,8 +53,18 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
/* trap error record accesses */
vcpu->arch.hcr_el2 |= HCR_TERR;
}
- if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
+
+ if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) {
vcpu->arch.hcr_el2 |= HCR_FWB;
+ } else {
+ /*
+ * For non-FWB CPUs, we trap VM ops (HCR_EL2.TVM) until M+C
+ * get set in SCTLR_EL1 such that we can detect when the guest
+ * MMU gets turned on and do the necessary cache maintenance
+ * then.
+ */
+ vcpu->arch.hcr_el2 |= HCR_TVM;
+ }
if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features))
vcpu->arch.hcr_el2 &= ~HCR_RW;
--
2.20.1
next prev parent reply other threads:[~2019-11-20 16:50 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 16:42 [GIT PULL] KVM/arm updates for 5.5 Marc Zyngier
2019-11-20 16:42 ` [PATCH 01/22] KVM: arm/arm64: Allow reporting non-ISV data aborts to userspace Marc Zyngier
2019-11-20 16:42 ` [PATCH 02/22] KVM: arm/arm64: Allow user injection of external data aborts Marc Zyngier
2019-11-20 16:42 ` [PATCH 03/22] KVM: arm64: Document PV-time interface Marc Zyngier
2019-11-20 16:42 ` [PATCH 04/22] KVM: arm/arm64: Factor out hypercall handling from PSCI code Marc Zyngier
2019-11-20 16:42 ` [PATCH 05/22] KVM: arm64: Implement PV_TIME_FEATURES call Marc Zyngier
2019-11-20 16:42 ` [PATCH 06/22] KVM: Implement kvm_put_guest() Marc Zyngier
2019-11-20 16:42 ` [PATCH 07/22] KVM: arm64: Support stolen time reporting via shared structure Marc Zyngier
2019-11-20 16:42 ` [PATCH 08/22] KVM: Allow kvm_device_ops to be const Marc Zyngier
2019-11-20 16:42 ` [PATCH 09/22] KVM: arm64: Provide VCPU attributes for stolen time Marc Zyngier
2019-11-20 16:42 ` [PATCH 10/22] arm/arm64: Provide a wrapper for SMCCC 1.1 calls Marc Zyngier
2019-11-20 16:42 ` [PATCH 11/22] arm/arm64: Make use of the SMCCC 1.1 wrapper Marc Zyngier
2019-11-20 16:42 ` [PATCH 12/22] arm64: Retrieve stolen time as paravirtualized guest Marc Zyngier
2019-11-20 16:42 ` [PATCH 13/22] KVM: arm64: Select TASK_DELAY_ACCT+TASKSTATS rather than SCHEDSTATS Marc Zyngier
2019-11-20 16:42 ` [PATCH 14/22] KVM: arm/arm64: Show halt poll counters in debugfs Marc Zyngier
2019-11-20 16:42 ` Marc Zyngier [this message]
2019-11-20 16:42 ` [PATCH 16/22] KVM: arm64: vgic-v4: Move the GICv4 residency flow to be driven by vcpu_load/put Marc Zyngier
2019-11-20 16:42 ` [PATCH 17/22] KVM: arm/arm64: vgic: Remove the declaration of kvm_send_userspace_msi() Marc Zyngier
2019-11-20 16:42 ` [PATCH 18/22] KVM: arm/arm64: vgic: Fix some comments typo Marc Zyngier
2019-11-20 16:42 ` [PATCH 19/22] KVM: arm/arm64: vgic: Don't rely on the wrong pending table Marc Zyngier
2019-11-20 16:42 ` [PATCH 20/22] KVM: arm/arm64: Let the timer expire in hardirq context on RT Marc Zyngier
2019-11-20 16:42 ` [PATCH 21/22] KVM: vgic-v4: Track the number of VLPIs per vcpu Marc Zyngier
2019-11-20 16:42 ` [PATCH 22/22] KVM: arm64: Opportunistically turn off WFI trapping when using direct LPI injection Marc Zyngier
2019-11-21 8:58 ` [GIT PULL] KVM/arm updates for 5.5 Paolo Bonzini
2019-11-21 9:06 ` Marc Zyngier
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