From: Kristina Martsenko Date: Thu, 16 Nov 2017 17:58:20 +0000 (+0000) Subject: arm64: KVM: fix VTTBR_BADDR_MASK BUG_ON off-by-one X-Git-Tag: v3.18.88~42 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=140db397a1440a325a144af1defa458e8330680b;p=thirdparty%2Fkernel%2Fstable.git arm64: KVM: fix VTTBR_BADDR_MASK BUG_ON off-by-one commit 26aa7b3b1c0fb3f1a6176a0c1847204ef4355693 upstream. VTTBR_BADDR_MASK is used to sanity check the size and alignment of the VTTBR address. It seems to currently be off by one, thereby only allowing up to 47-bit addresses (instead of 48-bit) and also insufficiently checking the alignment. This patch fixes it. As an example, with 4k pages, before this patch we have: PHYS_MASK_SHIFT = 48 VTTBR_X = 37 - 24 = 13 VTTBR_BADDR_SHIFT = 13 - 1 = 12 VTTBR_BADDR_MASK = ((1 << 35) - 1) << 12 = 0x00007ffffffff000 Which is wrong, because the mask doesn't allow bit 47 of the VTTBR address to be set, and only requires the address to be 12-bit (4k) aligned, while it actually needs to be 13-bit (8k) aligned because we concatenate two 4k tables. With this patch, the mask becomes 0x0000ffffffffe000, which is what we want. Fixes: 0369f6a34b9f ("arm64: KVM: EL2 register definitions") Reviewed-by: Suzuki K Poulose Reviewed-by: Christoffer Dall Signed-off-by: Kristina Martsenko Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 8afb863f5a9e3..333ddd45dd1f5 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -160,8 +160,7 @@ #define VTTBR_X (37 - VTCR_EL2_T0SZ_40B) #endif -#define VTTBR_BADDR_SHIFT (VTTBR_X - 1) -#define VTTBR_BADDR_MASK (((UL(1) << (PHYS_MASK_SHIFT - VTTBR_X)) - 1) << VTTBR_BADDR_SHIFT) +#define VTTBR_BADDR_MASK (((UL(1) << (PHYS_MASK_SHIFT - VTTBR_X)) - 1) << VTTBR_X) #define VTTBR_VMID_SHIFT (UL(48)) #define VTTBR_VMID_MASK (UL(0xFF) << VTTBR_VMID_SHIFT)