Juergen, thanks for following up on this.
X86 maintainers - If it helps let me also confirm that without this
patch the latest kernels *always* crash on VMware guest running HWv10
and earlier.
Please include the fix at your earliest.
Thanks,
Alok
On Mon, 2015-01-19 at 06:05 +0100, Juergen Gross wrote:
> PING!
>
> The patch repairs a bug with VMWARE, which has been reported by several
> users. All of them have confirmed the patch is working. And VMWARE has
> acked the patch. What else do you need to take it? It is available for
> over a month now!
>
> Juergen
>
> On 01/12/2015 06:15 AM, Juergen Gross wrote:
> > VMWare seems not to emulate the PAT MSR correctly: reaeding
> > MSR_IA32_CR_PAT returns 0 even after writing another value to it.
> >
> > Detect this bug and don't use the read value if it is 0.
> >
> > Commit bd809af16e3ab1f8d55b3e2928c47c67e2a865d2 ("x86: Enable PAT to
> > use cache mode translation tables") triggers this VMWare bug when the
> > kernel is booted as a VMWare guest.
> >
> > Reported-by: Jongman Heo <jongman....@samsung.com>
> > Signed-off-by: Juergen Gross <jgr...@suse.com>
> > Tested-by: Jongman Heo <jongman....@samsung.com>
> > Acked-by: Alok N Kataria <akata...@vmware.com>
> > ---
> > arch/x86/mm/pat.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
> > index edf299c..7ac6869 100644
> > --- a/arch/x86/mm/pat.c
> > +++ b/arch/x86/mm/pat.c
> > @@ -234,8 +234,13 @@ void pat_init(void)
> > PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
> >
> > /* Boot CPU check */
> > - if (!boot_pat_state)
> > + if (!boot_pat_state) {
> > rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
> > + if (!boot_pat_state) {
> > + pat_disable("PAT read returns always zero, disabled.");
> > + return;
> > + }
> > + }
> >
> > wrmsrl(MSR_IA32_CR_PAT, pat);
> >
> >
>
