On Thursday, October 29, 2015 04:42:20 PM Steven Wahl wrote: > We ran into this exact problem, pmap_change_attr not working right with large > bars. I had been working up to seeing if this compiles on the current head, > introducing myself to the community, seeing if this would be accepted. > > But looks like it's needed sooner, so in case it might save you some time, > here's the patch we developed for this problem. > > --> Steve Wahl, Dell Compellent, Eden Prairie, MN
Adding alc@, but on first blush this looks correct to me. > > commit 7d112aa8767390cb9dd020325a9f23aaac7fe5a0 > Author: swahl <[email protected]> > Date: Thu Oct 1 14:36:48 2015 -0500 > > CQ00492954: FreeBSD traps on call to pmap_change_attr() with large PLX BAR > > If an address passed to pmap_change_attr() refers to a virtual address, > the function must also change the direct mapping of this same > region (if any) to match, or intel says the result is undefined. > > But the original code did not check if the virtual address actually fell > within the direct mapped region before attempting to make this change. > The attempt to look up the direct mapped page entries returned NULL, and > this was dereferenced causing a panic. > > This is fixed by checking whether the address is outside of the direct > mapped range before trying to change the direct mapped entries. > > diff --git a/src/sys/amd64/amd64/pmap.c b/src/sys/amd64/amd64/pmap.c > index fe09ace..dee22de 100644 > --- a/src/sys/amd64/amd64/pmap.c > +++ b/src/sys/amd64/amd64/pmap.c > @@ -6268,7 +6268,7 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, > int mode) > */ > for (tmpva = base; tmpva < base + size; ) { > pdpe = pmap_pdpe(kernel_pmap, tmpva); > - if (*pdpe == 0) > + if (pdpe == NULL || *pdpe == 0) > return (EINVAL); > if (*pdpe & PG_PS) { > /* > @@ -6341,7 +6341,8 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, > int mode) > X86_PG_PDE_CACHE); > changed = TRUE; > } > - if (tmpva >= VM_MIN_KERNEL_ADDRESS) { > + if (tmpva >= VM_MIN_KERNEL_ADDRESS && > + (*pdpe & PG_PS_FRAME) < dmaplimit) { > if (pa_start == pa_end) { > /* Start physical address run. */ > pa_start = *pdpe & PG_PS_FRAME; > @@ -6370,7 +6371,8 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, > int mode) > X86_PG_PDE_CACHE); > changed = TRUE; > } > - if (tmpva >= VM_MIN_KERNEL_ADDRESS) { > + if (tmpva >= VM_MIN_KERNEL_ADDRESS && > + (*pde & PG_PS_FRAME) < dmaplimit) { > if (pa_start == pa_end) { > /* Start physical address run. */ > pa_start = *pde & PG_PS_FRAME; > @@ -6397,7 +6399,8 @@ pmap_change_attr_locked(vm_offset_t va, vm_size_t size, > int mode) > X86_PG_PTE_CACHE); > changed = TRUE; > } > - if (tmpva >= VM_MIN_KERNEL_ADDRESS) { > + if (tmpva >= VM_MIN_KERNEL_ADDRESS && > + (*pte & PG_FRAME) < dmaplimit) { > if (pa_start == pa_end) { > /* Start physical address run. */ > pa_start = *pte & PG_FRAME; > -- John Baldwin _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
