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Commit 3bf8e03d authored by Suzuki K Poulose's avatar Suzuki K Poulose Committed by Greg Kroah-Hartman
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KVM: arm64: Disable guest access to trace filter controls 



[ Upstream commit a354a64d91eec3e0f8ef0eed575b480fd75b999c ]

Disable guest access to the Trace Filter control registers.
We do not advertise the Trace filter feature to the guest
(ID_AA64DFR0_EL1: TRACE_FILT is cleared) already, but the guest
can still access the TRFCR_EL1 unless we trap it.

This will also make sure that the guest cannot fiddle with
the filtering controls set by a nvhe host.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210323120647.454211-3-suzuki.poulose@arm.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 6e873559

arch/arm64/include/asm/kvm_arm.h

+1 −0
Original line number Diff line number Diff line
@@ -198,6 +198,7 @@ 
#define CPTR_EL2_DEFAULT	CPTR_EL2_RES1



/* Hyp Debug Configuration Register bits */

#define MDCR_EL2_TTRF		(1 << 19)

#define MDCR_EL2_TPMS		(1 << 14)

#define MDCR_EL2_E2PB_MASK	(UL(0x3))

#define MDCR_EL2_E2PB_SHIFT	(UL(12))

arch/arm64/kvm/debug.c

+2 −0
Original line number Diff line number Diff line
@@ -100,6 +100,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) 
 *  - Debug ROM Address (MDCR_EL2_TDRA)

 *  - OS related registers (MDCR_EL2_TDOSA)

 *  - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB)

 *  - Self-hosted Trace Filter controls (MDCR_EL2_TTRF)

 *

 * Additionally, KVM only traps guest accesses to the debug registers if

 * the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY
@@ -123,6 +124,7 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) 
	vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;

	vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |

				MDCR_EL2_TPMS |

				MDCR_EL2_TTRF |

				MDCR_EL2_TPMCR |

				MDCR_EL2_TDRA |

				MDCR_EL2_TDOSA);