linux-kernel - [PATCH 4.14 22/41] KVM: arm/arm64: Reduce verbosity of KVM init log

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Date:   Mon, 19 Mar 2018 19:08:22 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Will Deacon <will.deacon@....com>,
        Christoffer Dall <cdall@...nel.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Marc Zyngier <marc.zyngier@....com>
Subject: [PATCH 4.14 22/41] KVM: arm/arm64: Reduce verbosity of KVM init log

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ard Biesheuvel <ard.biesheuvel@...aro.org>

commit 76600428c3677659e3c3633bb4f2ea302220a275 upstream.

On my GICv3 system, the following is printed to the kernel log at boot:

   kvm [1]: 8-bit VMID
   kvm [1]: IDMAP page: d20e35000
   kvm [1]: HYP VA range: 800000000000:ffffffffffff
   kvm [1]: vgic-v2@...20000
   kvm [1]: GIC system register CPU interface enabled
   kvm [1]: vgic interrupt IRQ1
   kvm [1]: virtual timer IRQ4
   kvm [1]: Hyp mode initialized successfully

The KVM IDMAP is a mapping of a statically allocated kernel structure,
and so printing its physical address leaks the physical placement of
the kernel when physical KASLR in effect. So change the kvm_info() to
kvm_debug() to remove it from the log output.

While at it, trim the output a bit more: IRQ numbers can be found in
/proc/interrupts, and the HYP VA and vgic-v2 lines are not highly
informational either.

Cc: <stable@...r.kernel.org>
Acked-by: Will Deacon <will.deacon@....com>
Acked-by: Christoffer Dall <cdall@...nel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 virt/kvm/arm/arch_timer.c   |    2 +-
 virt/kvm/arm/mmu.c          |    6 +++---
 virt/kvm/arm/vgic/vgic-v2.c |    2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -602,7 +602,7 @@ int kvm_timer_hyp_init(void)
 		return err;
 	}
 
-	kvm_info("virtual timer IRQ%d\n", host_vtimer_irq);
+	kvm_debug("virtual timer IRQ%d\n", host_vtimer_irq);
 
 	cpuhp_setup_state(CPUHP_AP_KVM_ARM_TIMER_STARTING,
 			  "kvm/arm/timer:starting", kvm_timer_starting_cpu,
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1760,9 +1760,9 @@ int kvm_mmu_init(void)
 	 */
 	BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);
 
-	kvm_info("IDMAP page: %lx\n", hyp_idmap_start);
-	kvm_info("HYP VA range: %lx:%lx\n",
-		 kern_hyp_va(PAGE_OFFSET), kern_hyp_va(~0UL));
+	kvm_debug("IDMAP page: %lx\n", hyp_idmap_start);
+	kvm_debug("HYP VA range: %lx:%lx\n",
+		  kern_hyp_va(PAGE_OFFSET), kern_hyp_va(~0UL));
 
 	if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) &&
 	    hyp_idmap_start <  kern_hyp_va(~0UL) &&
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -380,7 +380,7 @@ int vgic_v2_probe(const struct gic_kvm_i
 	kvm_vgic_global_state.type = VGIC_V2;
 	kvm_vgic_global_state.max_gic_vcpus = VGIC_V2_MAX_CPUS;
 
-	kvm_info("vgic-v2@...x\n", info->vctrl.start);
+	kvm_debug("vgic-v2@...x\n", info->vctrl.start);
 
 	return 0;
 out: