[RFC PATCH 0/6] KVM: gmem: Implement error_remove_page

From: isaku.yamahata@intel.com
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
	Michael Roth <michael.roth@amd.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	erdemaktas@google.com, Sagi Shahar <sagis@google.com>,
	David Matlack <dmatlack@google.com>,
	Kai Huang <kai.huang@intel.com>,
	Zhi Wang <zhi.wang.linux@gmail.com>,
	chen.bo@intel.com, linux-coco@lists.linux.dev,
	Chao Peng <chao.p.peng@linux.intel.com>,
	Ackerley Tng <ackerleytng@google.com>,
	Vishal Annapurve <vannapurve@google.com>,
	Yuan Yao <yuan.yao@linux.intel.com>,
	Jarkko Sakkinen <jarkko@kernel.org>,
	Xu Yilun <yilun.xu@intel.com>,
	Quentin Perret <qperret@google.com>,
	wei.w.wang@intel.com, Fuad Tabba <tabba@google.com>
Subject: [RFC PATCH 0/6] KVM: gmem: Implement error_remove_page
Date: Wed, 13 Sep 2023 03:48:49 -0700	[thread overview]
Message-ID: <cover.1694599703.git.isaku.yamahata@intel.com> (raw)

From: Isaku Yamahata <isaku.yamahata@intel.com>

This patch series is to share my progress on the KVM gmem error_remove_page task.
Although I'm still working on test cases, I don't want to hold the patches
locally until I finish test cases.

- Update error_remove_page method.  Unmap gfn on poisoned pages.  Pass related
  arguments.  Unfortunately, the error_remove_page callback is passed struct
  page.  So the callback can't know about the actual poisoned address and range.
  The memory poisoning would be based on cache line size, though.
- Add a new flag to KVM_EXIT_MEMORY_FAULT to indicate the page is poisoned.
- Add check in faultin_pfn_private.  When the page is poisoned,
  KVM_EXIT_MEMORY_FAULT(HWPOISON).
- Only test case for ioctl(FIBMAP).  Test cases are TODO.

TODOs
- Implement test cases to inject HWPOISON or MCE by hwpoison
  (/sys/kernel/debug/hwpoison/corrupt-pfn) or MCE injection
  (/sys/kernel/debug/mce-inject).
- Update qemu to handle KVM_EXIT_MEMORY_FAULT(HWPOISON)
- Update TDX KVM to handle it and Add test cases for TDX.
- Try to inject HWPOISON as soon as the poison is detected.

Isaku Yamahata (6):
  KVM: guest_memfd: Add config to show the capability to handle error
    page
  KVM: guestmem_fd: Make error_remove_page callback to unmap guest
    memory
  KVM: guest_memfd, x86: MEMORY_FAULT exit with hw poisoned page
  KVM: guest_memfd: Implemnet bmap inode operation
  KVM: selftests: Add selftest for guest_memfd() fibmap
  KVM: X86: Allow KVM gmem hwpoison test cases

 arch/x86/kvm/Kconfig                          |  2 +
 arch/x86/kvm/mmu/mmu.c                        | 21 +++--
 include/linux/kvm_host.h                      |  2 +
 include/uapi/linux/kvm.h                      |  3 +-
 .../testing/selftests/kvm/guest_memfd_test.c  | 45 ++++++++++
 virt/kvm/Kconfig                              |  7 ++
 virt/kvm/guest_mem.c                          | 82 +++++++++++++++----
 7 files changed, 139 insertions(+), 23 deletions(-)

base-commit: a5accd8596fa84b9fe00076444b5ef628d2351b9
-- 
2.25.1