linux-kernel - [PATCH 5.15 081/207] KVM: arm64: Avoid setting the upper 32 bits of TCR_EL2 and CPTR

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Date:   Mon,  6 Dec 2021 15:55:35 +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, Catalin Marinas <catalin.marinas@....com>,
        Chris January <Chris.January@....com>,
        Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>
Subject: [PATCH 5.15 081/207] KVM: arm64: Avoid setting the upper 32 bits of TCR_EL2 and CPTR_EL2 to 1

From: Catalin Marinas <catalin.marinas@....com>

commit 1f80d15020d7f130194821feb1432b67648c632d upstream.

Having a signed (1 << 31) constant for TCR_EL2_RES1 and CPTR_EL2_TCPAC
causes the upper 32-bit to be set to 1 when assigning them to a 64-bit
variable. Bit 32 in TCR_EL2 is no longer RES0 in ARMv8.7: with FEAT_LPA2
it changes the meaning of bits 49:48 and 9:8 in the stage 1 EL2 page
table entries. As a result of the sign-extension, a non-VHE kernel can
no longer boot on a model with ARMv8.7 enabled.

CPTR_EL2 still has the top 32 bits RES0 but we should preempt any future
problems

Make these top bit constants unsigned as per commit df655b75c43f
("arm64: KVM: Avoid setting the upper 32 bits of VTCR_EL2 to 1").

Signed-off-by: Catalin Marinas <catalin.marinas@....com>
Reported-by: Chris January <Chris.January@....com>
Cc: <stable@...r.kernel.org>
Cc: Will Deacon <will@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Link: https://lore.kernel.org/r/20211125152014.2806582-1-catalin.marinas@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/arm64/include/asm/kvm_arm.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -91,7 +91,7 @@
 #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
 
 /* TCR_EL2 Registers bits */
-#define TCR_EL2_RES1		((1 << 31) | (1 << 23))
+#define TCR_EL2_RES1		((1U << 31) | (1 << 23))
 #define TCR_EL2_TBI		(1 << 20)
 #define TCR_EL2_PS_SHIFT	16
 #define TCR_EL2_PS_MASK		(7 << TCR_EL2_PS_SHIFT)
@@ -276,7 +276,7 @@
 #define CPTR_EL2_TFP_SHIFT 10
 
 /* Hyp Coprocessor Trap Register */
-#define CPTR_EL2_TCPAC	(1 << 31)
+#define CPTR_EL2_TCPAC	(1U << 31)
 #define CPTR_EL2_TAM	(1 << 30)
 #define CPTR_EL2_TTA	(1 << 20)
 #define CPTR_EL2_TFP	(1 << CPTR_EL2_TFP_SHIFT)