[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] [PATCH v1 02/10] KVM: x86/mmu: Prepare kvm_is_mmio_pfn() for PG_reserved changes
- To: Dan Williams <dan.j.williams@xxxxxxxxx>
- From: David Hildenbrand <david@xxxxxxxxxx>
- Date: Tue, 5 Nov 2019 12:09:33 +0100
- Cc: linux-hyperv@xxxxxxxxxxxxxxx, Michal Hocko <mhocko@xxxxxxxx>, Radim Krčmář <rkrcmar@xxxxxxxxxx>, KVM list <kvm@xxxxxxxxxxxxxxx>, Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx>, KarimAllah Ahmed <karahmed@xxxxxxxxx>, Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>, Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>, Alexander Duyck <alexander.duyck@xxxxxxxxx>, Michal Hocko <mhocko@xxxxxxxxxx>, Paul Mackerras <paulus@xxxxxxxxxx>, Linux MM <linux-mm@xxxxxxxxx>, Paul Mackerras <paulus@xxxxxxxxx>, Michael Ellerman <mpe@xxxxxxxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>, Wanpeng Li <wanpengli@xxxxxxxxxxx>, Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>, "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>, Thomas Gleixner <tglx@xxxxxxxxxxxxx>, Kees Cook <keescook@xxxxxxxxxxxx>, devel@xxxxxxxxxxxxxxxxxxxx, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>, "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>, Joerg Roedel <joro@xxxxxxxxxx>, X86 ML <x86@xxxxxxxxxx>, YueHaibing <yuehaibing@xxxxxxxxxx>, "Matthew Wilcox \(Oracle\)" <willy@xxxxxxxxxxxxx>, Mike Rapoport <rppt@xxxxxxxxxxxxx>, Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Ingo Molnar <mingo@xxxxxxxxxx>, Vlastimil Babka <vbabka@xxxxxxx>, Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>, Oscar Salvador <osalvador@xxxxxxx>, "Isaac J. Manjarres" <isaacm@xxxxxxxxxxxxxx>, Matt Sickler <Matt.Sickler@xxxxxxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, Anshuman Khandual <anshuman.khandual@xxxxxxx>, Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>, kvm-ppc@xxxxxxxxxxxxxxx, Qian Cai <cai@xxxxxx>, Alex Williamson <alex.williamson@xxxxxxxxxx>, Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>, Borislav Petkov <bp@xxxxxxxxx>, Nicholas Piggin <npiggin@xxxxxxxxx>, Andy Lutomirski <luto@xxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>, Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>, Allison Randal <allison@xxxxxxxxxxx>, Jim Mattson <jmattson@xxxxxxxxxx>, Christophe Leroy <christophe.leroy@xxxxxx>, Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>, Cornelia Huck <cohuck@xxxxxxxxxx>, Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Sean Christopherson <sean.j.christopherson@xxxxxxxxx>, Johannes Weiner <hannes@xxxxxxxxxxx>, Paolo Bonzini <pbonzini@xxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, linuxppc-dev <linuxppc-dev@xxxxxxxxxxxxxxxx>
- Delivery-date: Tue, 05 Nov 2019 11:10:05 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 05.11.19 02:37, Dan Williams wrote:
On Thu, Oct 24, 2019 at 5:10 AM David Hildenbrand <david@xxxxxxxxxx> wrote:
Right now, ZONE_DEVICE memory is always set PG_reserved. We want to
change that.
KVM has this weird use case that you can map anything from /dev/mem
into the guest. pfn_valid() is not a reliable check whether the memmap
was initialized and can be touched. pfn_to_online_page() makes sure
that we have an initialized memmap (and don't have ZONE_DEVICE memory).
Rewrite kvm_is_mmio_pfn() to make sure the function produces the
same result once we stop setting ZONE_DEVICE pages PG_reserved.
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: KarimAllah Ahmed <karahmed@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 24c23c66b226..f03089a336de 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2962,20 +2962,25 @@ static bool mmu_need_write_protect(struct kvm_vcpu
*vcpu, gfn_t gfn,
static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)
{
+ struct page *page = pfn_to_online_page(pfn);
+
+ /*
+ * ZONE_DEVICE pages are never online. Online pages that are reserved
+ * either indicate the zero page or MMIO pages.
+ */
+ if (page)
+ return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn));
+
+ /*
+ * Anything with a valid (but not online) memmap could be ZONE_DEVICE.
+ * Treat only UC/UC-/WC pages as MMIO.
You might clarify that ZONE_DEVICE pages that belong to WB cacheable
pmem have the correct memtype established by devm_memremap_pages().
/*
* Anything with a valid (but not online) memmap could be ZONE_DEVICE.
* Treat only UC/UC-/WC pages as MMIO. devm_memremap_pages() established
* the correct memtype for WB cacheable ZONE_DEVICE pages.
*/
Thanks!
Other than that, feel free to add:
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
--
Thanks,
David / dhildenb
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
