Re: [PATCH v9 6/6] KVM: x86/mmu: Handle non-refcounted pages

From: Dmitry Osipenko
Date: Mon Sep 18 2023 - 05:59:12 EST


On 9/11/23 05:16, David Stevens wrote:
> From: David Stevens <stevensd@xxxxxxxxxxxx>
>
> Handle non-refcounted pages in __kvm_faultin_pfn. This allows the host
> to map memory into the guest that is backed by non-refcounted struct
> pages - for example, the tail pages of higher order non-compound pages
> allocated by the amdgpu driver via ttm_pool_alloc_page.
>
> The bulk of this change is tracking the is_refcounted_page flag so that
> non-refcounted pages don't trigger page_count() == 0 warnings. This is
> done by storing the flag in an unused bit in the sptes. There are no
> bits available in PAE SPTEs, so non-refcounted pages can only be handled
> on TDP and x86-64.
>
> Signed-off-by: David Stevens <stevensd@xxxxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/mmu.c | 52 +++++++++++++++++++++++----------
> arch/x86/kvm/mmu/mmu_internal.h | 1 +
> arch/x86/kvm/mmu/paging_tmpl.h | 8 +++--
> arch/x86/kvm/mmu/spte.c | 4 ++-
> arch/x86/kvm/mmu/spte.h | 12 +++++++-
> arch/x86/kvm/mmu/tdp_mmu.c | 22 ++++++++------
> include/linux/kvm_host.h | 3 ++
> virt/kvm/kvm_main.c | 6 ++--
> 8 files changed, 76 insertions(+), 32 deletions(-)

Could you please tell which kernel tree you used for the base of this
series? This patch #6 doesn't apply cleanly to stable/mainline/next/kvm

error: sha1 information is lacking or useless (arch/x86/kvm/mmu/mmu.c).
error: could not build fake ancestor

--
Best regards,
Dmitry