[PATCH AUTOSEL 4.14 1/5] KVM: arm64: Hide system instruction access to Trace registers

[PATCH AUTOSEL 4.14 1/5] KVM: arm64: Hide system instruction access to Trace registers

[Sasha Levin]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

[ Upstream commit 1d676673d665fd2162e7e466dcfbe5373bfdb73e ]

Currently we advertise the ID_AA6DFR0_EL1.TRACEVER for the guest,
when the trace register accesses are trapped (CPTR_EL2.TTA == 1).
So, the guest will get an undefined instruction, if trusts the
ID registers and access one of the trace registers.
Lets be nice to the guest and hide the feature to avoid
unexpected behavior.

Even though this can be done at KVM sysreg emulation layer,
we do this by removing the TRACEVER from the sanitised feature
register field. This is fine as long as the ETM drivers
can handle the individual trace units separately, even
when there are differences among the CPUs.

Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210323120647.454211-2-suzuki.poulose@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm64/kernel/cpufeature.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 174aa12fb8b1..1481e18aa5ca 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -230,7 +230,6 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
 	 * of support.
 	 */
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6),
 	ARM64_FTR_END,
 };
-- 
2.30.2


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[PATCH AUTOSEL 4.14 2/5] KVM: arm64: Disable guest access to trace filter controls

[Sasha Levin]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

[ 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: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210323120647.454211-3-suzuki.poulose@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm64/include/asm/kvm_arm.h | 1 +
 arch/arm64/kvm/debug.c           | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index f88611e241f0..72ed11292df3 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -191,6 +191,7 @@
 #define CPTR_EL2_DEFAULT	0x000033ff
 
 /* 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 dbadfaf850a7..2da4f45ab0bb 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -96,6 +96,7 @@ 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
@@ -118,6 +119,7 @@ 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);
-- 
2.30.2


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[PATCH AUTOSEL 4.14 3/5] drm/imx: imx-ldb: fix out of bounds array access warning

[Sasha Levin]

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit 33ce7f2f95cabb5834cf0906308a5cb6103976da ]

When CONFIG_OF is disabled, building with 'make W=1' produces warnings
about out of bounds array access:

drivers/gpu/drm/imx/imx-ldb.c: In function 'imx_ldb_set_clock.constprop':
drivers/gpu/drm/imx/imx-ldb.c:186:8: error: array subscript -22 is below array bounds of 'struct clk *[4]' [-Werror=array-bounds]

Add an error check before the index is used, which helps with the
warning, as well as any possible other error condition that may be
triggered at runtime.

The warning could be fixed by adding a Kconfig depedency on CONFIG_OF,
but Liu Ying points out that the driver may hit the out-of-bounds
problem at runtime anyway.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/imx/imx-ldb.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
index d38648a7ef2d..d88ac6f2222a 100644
--- a/drivers/gpu/drm/imx/imx-ldb.c
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -206,6 +206,11 @@ static void imx_ldb_encoder_enable(struct drm_encoder *encoder)
 	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
 	int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
 
+	if (mux < 0 || mux >= ARRAY_SIZE(ldb->clk_sel)) {
+		dev_warn(ldb->dev, "%s: invalid mux %d\n", __func__, mux);
+		return;
+	}
+
 	drm_panel_prepare(imx_ldb_ch->panel);
 
 	if (dual) {
@@ -264,6 +269,11 @@ imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder,
 	int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
 	u32 bus_format = imx_ldb_ch->bus_format;
 
+	if (mux < 0 || mux >= ARRAY_SIZE(ldb->clk_sel)) {
+		dev_warn(ldb->dev, "%s: invalid mux %d\n", __func__, mux);
+		return;
+	}
+
 	if (mode->clock > 170000) {
 		dev_warn(ldb->dev,
 			 "%s: mode exceeds 170 MHz pixel clock\n", __func__);
-- 
2.30.2


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