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[PATCHv15,6/9] KVM: arm64: Add a flag to disable MMIO trace for nVHE KVM

Message ID b1656f2f05147357b2b698db1196be6bab16f7f7.1652891705.git.quic_saipraka@quicinc.com
State Accepted
Commit 451f2f1c908ba6225e2de82c53eae399f9d342c0
Headers show
Series lib/rwmmio/arm64: Add support to trace register reads/writes | expand

Commit Message

Sai Prakash Ranjan May 18, 2022, 4:44 p.m. UTC 
Add a generic flag (__DISABLE_TRACE_MMIO__) to disable MMIO
tracing in nVHE KVM as the tracepoint and MMIO logging symbols
should not be visible at nVHE KVM as there is no way to execute
them. It can also be used to disable MMIO tracing for specific
drivers.

Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
---
 arch/arm64/kvm/hyp/nvhe/Makefile | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
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Patch

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index f9fe4dc21b1f..87d22a18b7a5 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -4,7 +4,12 @@ 
 #
 
 asflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS
-ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS
+
+# Tracepoint and MMIO logging symbols should not be visible at nVHE KVM as
+# there is no way to execute them and any such MMIO access from nVHE KVM
+# will explode instantly (Words of Marc Zyngier). So introduce a generic flag
+# __DISABLE_TRACE_MMIO__ to disable MMIO tracing for nVHE KVM.
+ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS -D__DISABLE_TRACE_MMIO__
 
 hostprogs := gen-hyprel
 HOST_EXTRACFLAGS += -I$(objtree)/include