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BACKPORT: arm64: KVM: Enable access to TRBE support for host

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For a nvhe host, the EL2 must allow the EL1&0 translation
regime for TraceBuffer (MDCR_EL2.E2TB == 0b11). This must
be saved/restored over a trip to the guest. Also, before
entering the guest, we must flush any trace data if the
TRBE was enabled. And we must prohibit the generation
of trace while we are in EL1 by clearing the TRFCR_EL1.

For vhe, the EL2 must prevent the EL1 access to the Trace
Buffer.

The MDCR_EL2 bit definitions for TRBE are available here :

  https://developer.arm.com/documentation/ddi0601/2020-12/AArch64-Registers/

Bug: 174685394
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210405164307.1720226-8-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
(cherry picked from commit a1319260bf62951e279ea228f682bf4b8834a3c2)
[Conflict:
 - arch/arm64/kvm/debug.c
 - arch/arm64/kvm/hyp/nvhe/debug-sr.c

Trivial conflicts except for one  which tried to replce

	kvm_arm_setup_mdcr_el2(vcpu);

we rejected that hunk.]
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Change-Id: I88316a7b2d7b7b23a01914a7de0a2898c4a66afa
This commit is contained in:
Suzuki K Poulose 2021-04-05 17:42:54 +01:00 committed by Todd Kjos
parent b6b0927eac
commit ee7e80c81b
3 changed files with 19 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/arm64/include/asm/kvm_host.h
View File

@ -406,6 +406,7 @@ struct kvm_vcpu_arch {
#define KVM_ARM64_PENDING_EXCEPTION (1 << 8) /* Exception pending */
#define KVM_ARM64_EXCEPT_MASK (7 << 9) /* Target EL/MODE */
#define KVM_ARM64_DEBUG_STATE_SAVE_SPE (1 << 12) /* Save SPE context if active */
#define KVM_ARM64_DEBUG_STATE_SAVE_TRBE (1 << 13) /* Save TRBE context if active */
/*
* When KVM_ARM64_PENDING_EXCEPTION is set, KVM_ARM64_EXCEPT_MASK can

16
arch/arm64/kvm/debug.c
View File

@ -141,7 +141,13 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
* @vcpu: the vcpu pointer
*
* This is called before each entry into the hypervisor to setup any
* debug related registers.
* debug related registers. Currently this just ensures we will trap
* access to:
* - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR)
* - Debug ROM Address (MDCR_EL2_TDRA)
* - OS related registers (MDCR_EL2_TDOSA)
* - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB)
* - Self-hosted Trace (MDCR_EL2_TTRF/MDCR_EL2_E2TB)
*
* Additionally, KVM only traps guest accesses to the debug registers if
* the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY
@ -280,9 +286,15 @@ void kvm_arch_vcpu_load_debug_state_flags(struct kvm_vcpu *vcpu)
if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_PMSVER_SHIFT) &&
!(read_sysreg_s(SYS_PMBIDR_EL1) & BIT(SYS_PMBIDR_EL1_P_SHIFT)))
vcpu->arch.flags |= KVM_ARM64_DEBUG_STATE_SAVE_SPE;
/* Check if we have TRBE implemented and available at the host */
if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_TRBE_SHIFT) &&
!(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_PROG))
vcpu->arch.flags |= KVM_ARM64_DEBUG_STATE_SAVE_TRBE;
}
void kvm_arch_vcpu_put_debug_state_flags(struct kvm_vcpu *vcpu)
{
vcpu->arch.flags &= ~KVM_ARM64_DEBUG_STATE_SAVE_SPE;
vcpu->arch.flags &= ~(KVM_ARM64_DEBUG_STATE_SAVE_SPE |
KVM_ARM64_DEBUG_STATE_SAVE_TRBE);
}

16
arch/arm64/kvm/hyp/nvhe/debug-sr.c
View File

@ -54,18 +54,8 @@ static void __debug_restore_spe(u64 pmscr_el1)
static void __debug_save_trace(u64 *trfcr_el1)
{
*trfcr_el1 = 0;
/* Check if we have TRBE */
if (!cpuid_feature_extract_unsigned_field(read_sysreg(id_aa64dfr0_el1),
ID_AA64DFR0_TRBE_SHIFT))
return;
/* Check we can access the TRBE */
if ((read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_PROG))
return;
/* Check if the TRBE is enabled */
if (!(read_sysreg_s(SYS_TRBLIMITR_EL1) & TRBLIMITR_ENABLE))
return;
@ -97,7 +87,8 @@ void __debug_save_host_buffers_nvhe(struct kvm_vcpu *vcpu)
if (vcpu->arch.flags & KVM_ARM64_DEBUG_STATE_SAVE_SPE)
__debug_save_spe(&vcpu->arch.host_debug_state.pmscr_el1);
/* Disable and flush Self-Hosted Trace generation */
__debug_save_trace(&vcpu->arch.host_debug_state.trfcr_el1);
if (vcpu->arch.flags & KVM_ARM64_DEBUG_STATE_SAVE_TRBE)
__debug_save_trace(&vcpu->arch.host_debug_state.trfcr_el1);
}
void __debug_switch_to_guest(struct kvm_vcpu *vcpu)
@ -109,7 +100,8 @@ void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.flags & KVM_ARM64_DEBUG_STATE_SAVE_SPE)
__debug_restore_spe(vcpu->arch.host_debug_state.pmscr_el1);
__debug_restore_trace(vcpu->arch.host_debug_state.trfcr_el1);
if (vcpu->arch.flags & KVM_ARM64_DEBUG_STATE_SAVE_TRBE)
__debug_restore_trace(vcpu->arch.host_debug_state.trfcr_el1);
}
void __debug_switch_to_host(struct kvm_vcpu *vcpu)