Re: [EXT] Re: [PATCH v2] target/riscv: Fix incorrect PTE merge in walk_pte

[Ralf Ramsauer]

On 22/04/2022 04:54, Bin Meng wrote:
> On Fri, Apr 22, 2022 at 10:53 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> > On Tue, Apr 5, 2022 at 1:34 AM Ralf Ramsauer
> > <ralf.ramsauer@oth-regensburg.de> wrote:
> > > Two non-subsequent PTEs can be mapped to subsequent paddrs. In this
> > > case, walk_pte will erroneously merge them.
> > >
> > > Enforce the split up, by tracking the virtual base address.
> > >
> > > Let's say we have the mapping:
> > > 0x81200000 -> 0x89623000 (4K)
> > > 0x8120f000 -> 0x89624000 (4K)
> > >
> > > Before, walk_pte would have shown:
> > >
> > > vaddr            paddr            size             attr
> > > ---------------- ---------------- ---------------- -------
> > > 0000000081200000 0000000089623000 0000000000002000 rwxu-ad
> > >
> > > as it only checks for subsequent paddrs. With this patch, it becomes:
> > >
> > > vaddr            paddr            size             attr
> > > ---------------- ---------------- ---------------- -------
> > > 0000000081200000 0000000089623000 0000000000001000 rwxu-ad
> > > 000000008120f000 0000000089624000 0000000000001000 rwxu-ad
> > >
> > > Signed-off-by: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de>
> > > ---
> > >   target/riscv/monitor.c | 5 ++++-
> > >   1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/target/riscv/monitor.c b/target/riscv/monitor.c
> > > index 7efb4b62c1..9dc4cb1156 100644
> > > --- a/target/riscv/monitor.c
> > > +++ b/target/riscv/monitor.c
> > > @@ -84,6 +84,7 @@ static void walk_pte(Monitor *mon, hwaddr base, target_ulong 
> > > start,
> > >   {
> > >       hwaddr pte_addr;
> > >       hwaddr paddr;
> > > +    target_ulong last_start = -1;
> > >       target_ulong pgsize;
> > >       target_ulong pte;
> > >       int ptshift;
> > > @@ -116,7 +117,8 @@ static void walk_pte(Monitor *mon, hwaddr base, 
> > > target_ulong start,
> > >                    * contiguous mapped block details.
> > >                    */
> >
> > Please also update the comments above to mention the new case you added here.

Shall I provide a v3? No problem, if that makes your life easier. 
Otherwise, you could also squash attached comment on integration.

Thanks
  Ralf

diff --git a/target/riscv/monitor.c b/target/riscv/monitor.c
index 02512ed48f..1cb0932e03 100644
--- a/target/riscv/monitor.c
+++ b/target/riscv/monitor.c
@@ -143,9 +143,9 @@ static void walk_pte(Monitor *mon, hwaddr base, 
target_ulong start,
                  * A leaf PTE has been found
                  *
                  * If current PTE's permission bits differ from the 
last one,
-                 * or current PTE's ppn does not make a contiguous physical
-                 * address block together with the last one, print out 
the last
-                 * contiguous mapped block details.
+                * or the current PTE breaks up a contiguous virtual or
+                * physical mapping, address block together with the 
last one,
+                * print out the last contiguous mapped block details.
                  */
                 if ((*last_attr != attr) ||
                     (*last_paddr + *last_size != paddr) ||