This is a note to let you know that I've just added the patch titled
KVM: arm64: Disable guest access to trace filter controls
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-arm64-disable-guest-access-to-trace-filter-contr.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a316d204e0d50b8c88cea5df5245f165dc597730
Author: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Date: Tue Mar 23 12:06:30 2021 +0000
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@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210323120647.454211-3-suzuki.poulose@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 4e90c2debf70..94d4025acc0b 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -278,6 +278,7 @@
#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))
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index 7a7e425616b5..dbc890511631 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -89,6 +89,7 @@ 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
@@ -112,6 +113,7 @@ 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);
