[Linux-stable-mirror] [PATCH v4.4 backport] arm64: KVM: fix VTTBR_BADDR_MASK BUG_ON off-by-one
From: Kristina Martsenko kristina.martsenko@arm.com
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") Cc: stable@vger.kernel.org # 3.11.x Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Kristina Martsenko kristina.martsenko@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Christoffer Dall christoffer.dall@linaro.org --- arch/arm64/include/asm/kvm_arm.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 2d960f8588b0..ef8e13d379cb 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -164,8 +164,7 @@ #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)
Hi Christoffer,
On 12/12/17 12:50, Christoffer Dall wrote:
From: Kristina Martsenko kristina.martsenko@arm.com
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") Cc: stable@vger.kernel.org # 3.11.x Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Kristina Martsenko kristina.martsenko@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Christoffer Dall christoffer.dall@linaro.org
arch/arm64/include/asm/kvm_arm.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
Not sure if I'm missing something, but it seems like this patch (and the v3.18 one) were already applied to the stable trees. It's two of the arch/arm/ patches that failed to apply, not the arch/arm64/ ones.
Kristina
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 2d960f8588b0..ef8e13d379cb 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -164,8 +164,7 @@ #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)
On Tue, Dec 12, 2017 at 5:35 PM, Kristina Martsenko kristina.martsenko@arm.com wrote:
Hi Christoffer,
On 12/12/17 12:50, Christoffer Dall wrote:
From: Kristina Martsenko kristina.martsenko@arm.com
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") Cc: stable@vger.kernel.org # 3.11.x Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Kristina Martsenko kristina.martsenko@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Christoffer Dall christoffer.dall@linaro.org
arch/arm64/include/asm/kvm_arm.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
Not sure if I'm missing something, but it seems like this patch (and the v3.18 one) were already applied to the stable trees. It's two of the arch/arm/ patches that failed to apply, not the arch/arm64/ ones.
You're not missing anything - I accidentally copied the commit id from the e-mail that told me it successfully applied the patch, duh.
I'll fix the other one.
-Christoffer
linux-stable-mirror@lists.linaro.org
-
Christoffer Dall -
Kristina Martsenko