From c2360eaa0262a816faf8032b7762d0c73df2cc62 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 27 Jun 2022 14:46:20 +0100 Subject: [PATCH] target/arm: Fix qemu-system-arm handling of LPAE block descriptors for highmem In commit 39a1fd25287f5d we fixed a bug in the handling of LPAE block descriptors where we weren't correctly zeroing out some RES0 bits. However this fix has a bug because the calculation of the mask is done at the wrong width: in descaddr &= ~(page_size - 1); page_size is a target_ulong, so in the 'qemu-system-arm' binary it is only 32 bits, and the effect is that we always zero out the top 32 bits of the calculated address. Fix the calculation by forcing the mask to be calculated with the same type as descaddr. This only affects 32-bit CPUs which support LPAE (e.g. cortex-a15) when used on board models which put RAM or devices above the 4GB mark and when the 'qemu-system-arm' executable is being used. It was also masked in 7.0 by the main bug reported in https://gitlab.com/qemu-project/qemu/-/issues/1078 where the virt board incorrectly does not enable 'highmem' for 32-bit CPUs. The workaround is to use 'qemu-system-aarch64' with the same command line. Reported-by: He Zhe Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20220627134620.3190252-1-peter.maydell@linaro.org Fixes: 39a1fd25287f5de ("target/arm: Fix handling of LPAE block descriptors") Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell --- target/arm/ptw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/arm/ptw.c b/target/arm/ptw.c index da478104f0..e71fc1f429 100644 --- a/target/arm/ptw.c +++ b/target/arm/ptw.c @@ -1257,7 +1257,7 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address, * clear the lower bits here before ORing in the low vaddr bits. */ page_size = (1ULL << ((stride * (4 - level)) + 3)); - descaddr &= ~(page_size - 1); + descaddr &= ~(hwaddr)(page_size - 1); descaddr |= (address & (page_size - 1)); /* Extract attributes from the descriptor */ attrs = extract64(descriptor, 2, 10)