From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
David Matlack <dmatlack@google.com>,
Lai Jiangshan <jiangshan.ljs@antgroup.com>
Subject: [PATCH V3 00/12] KVM: X86/MMU: Use one-off local shadow page for special roots
Date: Sat, 21 May 2022 21:16:48 +0800 [thread overview]
Message-ID: <20220521131700.3661-1-jiangshanlai@gmail.com> (raw)
From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Current code uses mmu->pae_root, mmu->pml4_root, and mmu->pml5_root to
setup special roots. The initialization code is complex and the roots
are not associated with struct kvm_mmu_page which causes the code more
complex.
So add new local shadow pages to simplify it.
The local shadow pages are associated with struct kvm_mmu_page and
VCPU-local.
The local shadow pages are created and freed when the roots are
changed (or one-off) which can be optimized but not in the patchset
since the re-creating is light way (in normal case only the struct
kvm_mmu_page needs to be re-allocated and sp->spt doens't, because
it is likely to be mmu->pae_root)
The patchset also fixes a possible bug described in:
https://lore.kernel.org/lkml/20220415103414.86555-1-jiangshanlai@gmail.com/
as patch1.
And the fixing is simplifed in patch9 with the help of local shadow page.
Note:
using_local_root_page() can be implemented in two ways.
static bool using_local_root_page(struct kvm_mmu *mmu)
{
return mmu->root_role.level == PT32E_ROOT_LEVEL ||
(!mmu->root_role.direct && mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL);
}
static bool using_local_root_page(struct kvm_mmu *mmu)
{
if (mmu->root_role.direct)
return mmu->root_role.level == PT32E_ROOT_LEVEL;
else
return mmu->cpu_role.base.level <= PT32E_ROOT_LEVEL;
}
I prefer the second way. But when I wrote the documents for them. I
couldn't explain well enough for the second way. Maybe I explained the
second way in a wrong aspect or my English is not qualified to explain
it.
So I put the first way in patch 2 and the second way in patch3.
Patch3 adds much more documents and changes the first way to the second
way. Patch3 can be discarded.
Changed from v2:
Add document for using_local_root_page()
Update many documents
Address review comments
Add a patch that fix a possible bug (and split other patches for patch9)
Changed from v1:
Rebase to newest kvm/queue. Slightly update patch4.
[V2]: https://lore.kernel.org/lkml/20220503150735.32723-1-jiangshanlai@gmail.com/
[V1]: https://lore.kernel.org/lkml/20220420132605.3813-1-jiangshanlai@gmail.com/
Lai Jiangshan (12):
KVM: X86/MMU: Verify PDPTE for nested NPT in PAE paging mode when page
fault
KVM: X86/MMU: Add using_local_root_page()
KVM: X86/MMU: Reduce a check in using_local_root_page() for common
cases
KVM: X86/MMU: Add local shadow pages
KVM: X86/MMU: Link PAE root pagetable with its children
KVM: X86/MMU: Activate local shadow pages and remove old logic
KVM: X86/MMU: Remove the check of the return value of to_shadow_page()
KVM: X86/MMU: Allocate mmu->pae_root for PAE paging on-demand
KVM: X86/MMU: Move the verifying of NPT's PDPTE in FNAME(fetch)
KVM: X86/MMU: Remove unused INVALID_PAE_ROOT and IS_VALID_PAE_ROOT
KVM: X86/MMU: Don't use mmu->pae_root when shadowing PAE NPT in 64-bit
host
KVM: X86/MMU: Remove mmu_alloc_special_roots()
arch/x86/include/asm/kvm_host.h | 5 +-
arch/x86/kvm/mmu/mmu.c | 575 ++++++++++++++------------------
arch/x86/kvm/mmu/mmu_internal.h | 10 -
arch/x86/kvm/mmu/paging_tmpl.h | 51 ++-
arch/x86/kvm/mmu/spte.c | 7 +
arch/x86/kvm/mmu/spte.h | 1 +
arch/x86/kvm/mmu/tdp_mmu.h | 7 +-
arch/x86/kvm/x86.c | 4 +-
8 files changed, 303 insertions(+), 357 deletions(-)
--
2.19.1.6.gb485710b
next reply other threads:[~2022-05-21 13:16 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-21 13:16 Lai Jiangshan [this message]
2022-05-21 13:16 ` [PATCH V3 01/12] KVM: X86/MMU: Verify PDPTE for nested NPT in PAE paging mode when page fault Lai Jiangshan
2022-07-19 21:17 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 02/12] KVM: X86/MMU: Add using_local_root_page() Lai Jiangshan
2022-05-26 21:28 ` David Matlack
2022-05-26 21:38 ` Sean Christopherson
2022-07-19 22:03 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 03/12] KVM: X86/MMU: Reduce a check in using_local_root_page() for common cases Lai Jiangshan
2022-05-21 13:16 ` [PATCH V3 04/12] KVM: X86/MMU: Add local shadow pages Lai Jiangshan
2022-05-26 21:38 ` David Matlack
2022-05-26 22:01 ` David Matlack
2022-07-20 0:35 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 05/12] KVM: X86/MMU: Link PAE root pagetable with its children Lai Jiangshan
2022-07-19 22:21 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 06/12] KVM: X86/MMU: Activate local shadow pages and remove old logic Lai Jiangshan
2022-05-21 13:16 ` [PATCH V3 07/12] KVM: X86/MMU: Remove the check of the return value of to_shadow_page() Lai Jiangshan
2022-07-19 22:42 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 08/12] KVM: X86/MMU: Allocate mmu->pae_root for PAE paging on-demand Lai Jiangshan
2022-07-19 23:08 ` Sean Christopherson
2022-07-20 0:07 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 09/12] KVM: X86/MMU: Move the verifying of NPT's PDPTE in FNAME(fetch) Lai Jiangshan
2022-07-19 23:21 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 10/12] KVM: X86/MMU: Remove unused INVALID_PAE_ROOT and IS_VALID_PAE_ROOT Lai Jiangshan
2022-07-19 23:11 ` Sean Christopherson
2022-05-21 13:16 ` [PATCH V3 11/12] KVM: X86/MMU: Don't use mmu->pae_root when shadowing PAE NPT in 64-bit host Lai Jiangshan
2022-07-19 23:26 ` Sean Christopherson
2022-07-19 23:27 ` Sean Christopherson
2022-05-21 13:17 ` [PATCH V3 12/12] KVM: X86/MMU: Remove mmu_alloc_special_roots() Lai Jiangshan
2022-05-26 8:49 ` [PATCH V3 00/12] KVM: X86/MMU: Use one-off local shadow page for special roots Lai Jiangshan
2022-05-26 20:27 ` David Matlack
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