On Thu, Oct 08, 2020 at 03:54:12PM +0800, yulei.kernel@xxxxxxxxx wrote: > From: Yulei Zhang <yuleixzhang@xxxxxxxxxxx> > > Dmem page is pfn invalid but not mmio. Support cacheable > dmem page for kvm. > > Signed-off-by: Chen Zhuo <sagazchen@xxxxxxxxxxx> > Signed-off-by: Yulei Zhang <yuleixzhang@xxxxxxxxxxx> > --- > arch/x86/kvm/mmu/mmu.c | 5 +++-- > include/linux/dmem.h | 7 +++++++ > mm/dmem.c | 7 +++++++ > 3 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 71aa3da2a0b7..0115c1767063 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -41,6 +41,7 @@ > #include <linux/hash.h> > #include <linux/kern_levels.h> > #include <linux/kthread.h> > +#include <linux/dmem.h> > > #include <asm/page.h> > #include <asm/memtype.h> > @@ -2962,9 +2963,9 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) > */ > (!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn)); > > - return !e820__mapped_raw_any(pfn_to_hpa(pfn), > + return (!e820__mapped_raw_any(pfn_to_hpa(pfn), > pfn_to_hpa(pfn + 1) - 1, > - E820_TYPE_RAM); > + E820_TYPE_RAM)) || (!is_dmem_pfn(pfn)); This is wrong. As is, the logic reads "A PFN is MMIO if it is INVALID && (!RAM || !DMEM)". The obvious fix would be to change it to "INVALID && !RAM && !DMEM", but that begs the question of whether or DMEM is reported as RAM. I don't see any e820 related changes in the series, i.e. no evidence that dmem yanks its memory out of the e820 tables, which makes me think this change is unnecessary. > } > > /* Bits which may be returned by set_spte() */
