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[PATCH v2] target/arm: Avoid target_ulong for physical address lookups

Ard Biesheuvel posted 1 patch 3 weeks, 4 days ago 
target/arm/internals.h |  4 ++--
target/arm/ptw.c       | 16 ++++++++--------
2 files changed, 10 insertions(+), 10 deletions(-)
[PATCH v2] target/arm: Avoid target_ulong for physical address lookups
Posted by Ard Biesheuvel 3 weeks, 4 days ago 
From: Ard Biesheuvel <ardb@kernel.org>

target_ulong is typedef'ed as a 32-bit integer when building the
qemu-system-arm target, and this is smaller than the size of an
intermediate physical address when LPAE is being used.

Given that Linux may place leaf level user page tables in high memory
when built for LPAE, the kernel will crash with an external abort as
soon as it enters user space when running with more than ~3 GiB of
system RAM.

So replace target_ulong with vaddr in places where it may carry an
address value that is not representable in 32 bits.

Fixes: f3639a64f602ea ("target/arm: Use softmmu tlbs for page table walking")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 target/arm/internals.h |  4 ++--
 target/arm/ptw.c       | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/target/arm/internals.h b/target/arm/internals.h
index c5d7b0b492..1e5da81ce9 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1449,7 +1449,7 @@ typedef struct GetPhysAddrResult {
  *  * for PSMAv5 based systems we don't bother to return a full FSR format
  *    value.
  */
-bool get_phys_addr(CPUARMState *env, target_ulong address,
+bool get_phys_addr(CPUARMState *env, vaddr address,
                    MMUAccessType access_type, ARMMMUIdx mmu_idx,
                    GetPhysAddrResult *result, ARMMMUFaultInfo *fi)
     __attribute__((nonnull));
@@ -1468,7 +1468,7 @@ bool get_phys_addr(CPUARMState *env, target_ulong address,
  * Similar to get_phys_addr, but use the given security space and don't perform
  * a Granule Protection Check on the resulting address.
  */
-bool get_phys_addr_with_space_nogpc(CPUARMState *env, target_ulong address,
+bool get_phys_addr_with_space_nogpc(CPUARMState *env, vaddr address,
                                     MMUAccessType access_type,
                                     ARMMMUIdx mmu_idx, ARMSecuritySpace space,
                                     GetPhysAddrResult *result,
diff --git a/target/arm/ptw.c b/target/arm/ptw.c
index defd6b84de..659855133c 100644
--- a/target/arm/ptw.c
+++ b/target/arm/ptw.c
@@ -74,13 +74,13 @@ typedef struct S1Translate {
 } S1Translate;
 
 static bool get_phys_addr_nogpc(CPUARMState *env, S1Translate *ptw,
-                                target_ulong address,
+                                vaddr address,
                                 MMUAccessType access_type,
                                 GetPhysAddrResult *result,
                                 ARMMMUFaultInfo *fi);
 
 static bool get_phys_addr_gpc(CPUARMState *env, S1Translate *ptw,
-                              target_ulong address,
+                              vaddr address,
                               MMUAccessType access_type,
                               GetPhysAddrResult *result,
                               ARMMMUFaultInfo *fi);
@@ -3217,7 +3217,7 @@ static ARMCacheAttrs combine_cacheattrs(uint64_t hcr,
  */
 static bool get_phys_addr_disabled(CPUARMState *env,
                                    S1Translate *ptw,
-                                   target_ulong address,
+                                   vaddr address,
                                    MMUAccessType access_type,
                                    GetPhysAddrResult *result,
                                    ARMMMUFaultInfo *fi)
@@ -3300,7 +3300,7 @@ static bool get_phys_addr_disabled(CPUARMState *env,
 }
 
 static bool get_phys_addr_twostage(CPUARMState *env, S1Translate *ptw,
-                                   target_ulong address,
+                                   vaddr address,
                                    MMUAccessType access_type,
                                    GetPhysAddrResult *result,
                                    ARMMMUFaultInfo *fi)
@@ -3405,7 +3405,7 @@ static bool get_phys_addr_twostage(CPUARMState *env, S1Translate *ptw,
 }
 
 static bool get_phys_addr_nogpc(CPUARMState *env, S1Translate *ptw,
-                                      target_ulong address,
+                                      vaddr address,
                                       MMUAccessType access_type,
                                       GetPhysAddrResult *result,
                                       ARMMMUFaultInfo *fi)
@@ -3542,7 +3542,7 @@ static bool get_phys_addr_nogpc(CPUARMState *env, S1Translate *ptw,
 }
 
 static bool get_phys_addr_gpc(CPUARMState *env, S1Translate *ptw,
-                              target_ulong address,
+                              vaddr address,
                               MMUAccessType access_type,
                               GetPhysAddrResult *result,
                               ARMMMUFaultInfo *fi)
@@ -3558,7 +3558,7 @@ static bool get_phys_addr_gpc(CPUARMState *env, S1Translate *ptw,
     return false;
 }
 
-bool get_phys_addr_with_space_nogpc(CPUARMState *env, target_ulong address,
+bool get_phys_addr_with_space_nogpc(CPUARMState *env, vaddr address,
                                     MMUAccessType access_type,
                                     ARMMMUIdx mmu_idx, ARMSecuritySpace space,
                                     GetPhysAddrResult *result,
@@ -3571,7 +3571,7 @@ bool get_phys_addr_with_space_nogpc(CPUARMState *env, target_ulong address,
     return get_phys_addr_nogpc(env, &ptw, address, access_type, result, fi);
 }
 
-bool get_phys_addr(CPUARMState *env, target_ulong address,
+bool get_phys_addr(CPUARMState *env, vaddr address,
                    MMUAccessType access_type, ARMMMUIdx mmu_idx,
                    GetPhysAddrResult *result, ARMMMUFaultInfo *fi)
 {
-- 
2.46.1.824.gd892dcdcdd-goog
Re: [PATCH v2] target/arm: Avoid target_ulong for physical address lookups
Posted by Philippe Mathieu-Daudé 2 weeks, 5 days ago 
On 27/9/24 09:10, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
> 
> target_ulong is typedef'ed as a 32-bit integer when building the
> qemu-system-arm target, and this is smaller than the size of an
> intermediate physical address when LPAE is being used.
> 
> Given that Linux may place leaf level user page tables in high memory
> when built for LPAE, the kernel will crash with an external abort as
> soon as it enters user space when running with more than ~3 GiB of
> system RAM.
> 
> So replace target_ulong with vaddr in places where it may carry an
> address value that is not representable in 32 bits.

Yay!

> Fixes: f3639a64f602ea ("target/arm: Use softmmu tlbs for page table walking")
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Tested-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>   target/arm/internals.h |  4 ++--
>   target/arm/ptw.c       | 16 ++++++++--------
>   2 files changed, 10 insertions(+), 10 deletions(-)
Re: [PATCH v2] target/arm: Avoid target_ulong for physical address lookups
Posted by Peter Maydell 3 weeks, 1 day ago 
On Fri, 27 Sept 2024 at 08:11, Ard Biesheuvel <ardb+git@google.com> wrote:
>
> From: Ard Biesheuvel <ardb@kernel.org>
>
> target_ulong is typedef'ed as a 32-bit integer when building the
> qemu-system-arm target, and this is smaller than the size of an
> intermediate physical address when LPAE is being used.
>
> Given that Linux may place leaf level user page tables in high memory
> when built for LPAE, the kernel will crash with an external abort as
> soon as it enters user space when running with more than ~3 GiB of
> system RAM.
>
> So replace target_ulong with vaddr in places where it may carry an
> address value that is not representable in 32 bits.
>
> Fixes: f3639a64f602ea ("target/arm: Use softmmu tlbs for page table walking")
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Tested-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Applied to target-arm.next, thanks (and tagged as for stable).

-- PMM

Patchew 2.1-devel-b67e4c2

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