Richard Henderson <richard.hender...@linaro.org> writes:
> User setting of -R reserved_va can lead to an assertion > failure in page_set_flags. Sanity check the value of > reserved_va and print an error message instead. Do not > allocate a commpage at all for m-profile cpus. I see this: TEST convd on i386 qemu-i386: Unable to reserve 0x100000000 bytes of virtual address space at 0x8000 (File exists) for use as guest address space (check your virtual memory ulimit setting, min_mmap_addr or reserve less using -R option) on the ubuntu aarch64 static build: https://gitlab.com/stsquad/qemu/-/jobs/4003523064 > > Signed-off-by: Richard Henderson <richard.hender...@linaro.org> > --- > linux-user/elfload.c | 37 +++++++++++++++++++++++++++---------- > 1 file changed, 27 insertions(+), 10 deletions(-) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index b068676340..0529430b1d 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -422,12 +422,32 @@ enum { > > static bool init_guest_commpage(void) > { > - abi_ptr commpage = HI_COMMPAGE & -qemu_host_page_size; > - void *want = g2h_untagged(commpage); > - void *addr = mmap(want, qemu_host_page_size, PROT_READ | PROT_WRITE, > - MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); > + ARMCPU *cpu = ARM_CPU(thread_cpu); > + abi_ptr want = HI_COMMPAGE & TARGET_PAGE_MASK; > + abi_ptr addr; > > - if (addr == MAP_FAILED) { > + /* > + * M-profile allocates maximum of 2GB address space, so can never > + * allocate the commpage. Skip it. > + */ > + if (arm_feature(&cpu->env, ARM_FEATURE_M)) { > + return true; > + } > + > + /* > + * If reserved_va does not cover the commpage, we get an assert > + * in page_set_flags. Produce an intelligent error instead. > + */ > + if (reserved_va != 0 && want + TARGET_PAGE_SIZE - 1 > reserved_va) { > + error_report("Allocating guest commpage: -R 0x%" PRIx64 " too small", > + (uint64_t)reserved_va + 1); > + exit(EXIT_FAILURE); > + } > + > + addr = target_mmap(want, TARGET_PAGE_SIZE, PROT_READ | PROT_WRITE, > + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); > + > + if (addr == -1) { > perror("Allocating guest commpage"); > exit(EXIT_FAILURE); > } > @@ -436,15 +456,12 @@ static bool init_guest_commpage(void) > } > > /* Set kernel helper versions; rest of page is 0. */ > - __put_user(5, (uint32_t *)g2h_untagged(0xffff0ffcu)); > + put_user_u32(5, 0xffff0ffcu); > > - if (mprotect(addr, qemu_host_page_size, PROT_READ)) { > + if (target_mprotect(addr, qemu_host_page_size, PROT_READ | PROT_EXEC)) { > perror("Protecting guest commpage"); > exit(EXIT_FAILURE); > } > - > - page_set_flags(commpage, commpage | ~qemu_host_page_mask, > - PAGE_READ | PAGE_EXEC | PAGE_VALID); > return true; > } -- Alex Bennée Virtualisation Tech Lead @ Linaro