Paolo Bonzini 3c7d3d188c KVM: x86/mmu: preserve pending TLB flush across calls to kvm_tdp_mmu_zap_sp
[ Upstream commit 315f02c60d9425b38eb8ad7f21b8a35e40db23f9 ]

Right now, if a call to kvm_tdp_mmu_zap_sp returns false, the caller
will skip the TLB flush, which is wrong.  There are two ways to fix
it:

- since kvm_tdp_mmu_zap_sp will not yield and therefore will not flush
  the TLB itself, we could change the call to kvm_tdp_mmu_zap_sp to
  use "flush |= ..."

- or we can chain the flush argument through kvm_tdp_mmu_zap_sp down
  to __kvm_tdp_mmu_zap_gfn_range.  Note that kvm_tdp_mmu_zap_sp will
  neither yield nor flush, so flush would never go from true to
  false.

This patch does the former to simplify application to stable kernels,
and to make it further clearer that kvm_tdp_mmu_zap_sp will not flush.

Cc: seanjc@google.com
Fixes: 048f49809c526 ("KVM: x86/mmu: Ensure TLBs are flushed for TDP MMU during NX zapping")
Cc: <stable@vger.kernel.org> # 5.10.x: 048f49809c: KVM: x86/mmu: Ensure TLBs are flushed for TDP MMU during NX zapping
Cc: <stable@vger.kernel.org> # 5.10.x: 33a3164161: KVM: x86/mmu: Don't allow TDP MMU to yield when recovering NX pages
Cc: <stable@vger.kernel.org>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-14 08:42:04 +02:00
2021-04-10 13:36:10 +02:00
2020-10-17 11:18:18 -07:00
2021-04-10 13:36:11 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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