| Message ID | 153154382700.34503.10197588570935341739.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Dan Williams <dan.j.williams@intel.com> wrote: > In preparation for using set_memory_uc() instead set_memory_np() for > isolating poison from speculation, teach the memtype code to sanitize > physical addresses vs __PHYSICAL_MASK. > > The motivation for using set_memory_uc() for this case is to allow > ongoing access to persistent memory pages via the pmem-driver + > memcpy_mcsafe() until the poison is repaired. > > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: Tony Luck <tony.luck@intel.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: <linux-edac@vger.kernel.org> > Cc: <x86@kernel.org> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> > --- > arch/x86/mm/pat.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c > index 1555bd7d3449..6788ffa990f8 100644 > --- a/arch/x86/mm/pat.c > +++ b/arch/x86/mm/pat.c > @@ -512,6 +512,17 @@ static int free_ram_pages_type(u64 start, u64 end) > return 0; > } > > +static u64 sanitize_phys(u64 address) > +{ > + /* > + * When changing the memtype for pages containing poison allow > + * for a "decoy" virtual address (bit 63 clear) passed to > + * set_memory_X(). __pa() on a "decoy" address results in a > + * physical address with it 63 set. > + */ > + return address & __PHYSICAL_MASK; s/it/bit Thanks, Ingo
On 07/24/2018 12:36 AM, Ingo Molnar wrote: > > * Dan Williams <dan.j.williams@intel.com> wrote: > >> In preparation for using set_memory_uc() instead set_memory_np() for >> isolating poison from speculation, teach the memtype code to sanitize >> physical addresses vs __PHYSICAL_MASK. >> >> The motivation for using set_memory_uc() for this case is to allow >> ongoing access to persistent memory pages via the pmem-driver + >> memcpy_mcsafe() until the poison is repaired. >> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: "H. Peter Anvin" <hpa@zytor.com> >> Cc: Tony Luck <tony.luck@intel.com> >> Cc: Borislav Petkov <bp@alien8.de> >> Cc: <linux-edac@vger.kernel.org> >> Cc: <x86@kernel.org> >> Signed-off-by: Dan Williams <dan.j.williams@intel.com> >> --- >> arch/x86/mm/pat.c | 16 ++++++++++++++++ >> 1 file changed, 16 insertions(+) >> >> diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c >> index 1555bd7d3449..6788ffa990f8 100644 >> --- a/arch/x86/mm/pat.c >> +++ b/arch/x86/mm/pat.c >> @@ -512,6 +512,17 @@ static int free_ram_pages_type(u64 start, u64 end) >> return 0; >> } >> >> +static u64 sanitize_phys(u64 address) >> +{ >> + /* >> + * When changing the memtype for pages containing poison allow >> + * for a "decoy" virtual address (bit 63 clear) passed to >> + * set_memory_X(). __pa() on a "decoy" address results in a >> + * physical address with it 63 set. >> + */ >> + return address & __PHYSICAL_MASK; > > s/it/bit Thanks Ingo! I'll update when I pull in the patch. > > Thanks, > > Ingo > _______________________________________________ > Linux-nvdimm mailing list > Linux-nvdimm@lists.01.org > https://lists.01.org/mailman/listinfo/linux-nvdimm >
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 1555bd7d3449..6788ffa990f8 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -512,6 +512,17 @@ static int free_ram_pages_type(u64 start, u64 end) return 0; } +static u64 sanitize_phys(u64 address) +{ + /* + * When changing the memtype for pages containing poison allow + * for a "decoy" virtual address (bit 63 clear) passed to + * set_memory_X(). __pa() on a "decoy" address results in a + * physical address with it 63 set. + */ + return address & __PHYSICAL_MASK; +} + /* * req_type typically has one of the: * - _PAGE_CACHE_MODE_WB @@ -533,6 +544,8 @@ int reserve_memtype(u64 start, u64 end, enum page_cache_mode req_type, int is_range_ram; int err = 0; + start = sanitize_phys(start); + end = sanitize_phys(end); BUG_ON(start >= end); /* end is exclusive */ if (!pat_enabled()) { @@ -609,6 +622,9 @@ int free_memtype(u64 start, u64 end) if (!pat_enabled()) return 0; + start = sanitize_phys(start); + end = sanitize_phys(end); + /* Low ISA region is always mapped WB. No need to track */ if (x86_platform.is_untracked_pat_range(start, end)) return 0;
In preparation for using set_memory_uc() instead set_memory_np() for isolating poison from speculation, teach the memtype code to sanitize physical addresses vs __PHYSICAL_MASK. The motivation for using set_memory_uc() for this case is to allow ongoing access to persistent memory pages via the pmem-driver + memcpy_mcsafe() until the poison is repaired. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: <linux-edac@vger.kernel.org> Cc: <x86@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- arch/x86/mm/pat.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)