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Sean Christopherson 5b774238e8 KVM: SVM: Fix off-by-one indexing when nullifying last used SEV VMCB
[ Upstream commit 179c6c27bf487273652efc99acd3ba512a23c137 ]

Use the raw ASID, not ASID-1, when nullifying the last used VMCB when
freeing an SEV ASID.  The consumer, pre_sev_run(), indexes the array by
the raw ASID, thus KVM could get a false negative when checking for a
different VMCB if KVM manages to reallocate the same ASID+VMCB combo for
a new VM.

Note, this cannot cause a functional issue _in the current code_, as
pre_sev_run() also checks which pCPU last did VMRUN for the vCPU, and
last_vmentry_cpu is initialized to -1 during vCPU creation, i.e. is
guaranteed to mismatch on the first VMRUN.  However, prior to commit
8a14fe4f0c ("kvm: x86: Move last_cpu into kvm_vcpu_arch as
last_vmentry_cpu"), SVM tracked pCPU on its own and zero-initialized the
last_cpu variable.  Thus it's theoretically possible that older versions
of KVM could miss a TLB flush if the first VMRUN is on pCPU0 and the ASID
and VMCB exactly match those of a prior VM.

Fixes: 70cd94e60c ("KVM: SVM: VMRUN should use associated ASID when SEV is enabled")
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-15 13:08:02 +02:00
Documentation userfaultfd: do not untag user pointers 2021-07-28 13:31:01 +02:00
LICENSES
arch KVM: SVM: Fix off-by-one indexing when nullifying last used SEV VMCB 2021-08-15 13:08:02 +02:00
block blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() 2021-08-12 13:20:58 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
drivers net/qla3xxx: fix schedule while atomic in ql_wait_for_drvr_lock and ql_adapter_reset 2021-08-12 13:21:05 +02:00
fs reiserfs: check directory items on read from disk 2021-08-12 13:21:05 +02:00
include tee: add tee_shm_alloc_kernel_buf() 2021-08-12 13:21:01 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel timers: Move clearing of base::timer_running under base:: Lock 2021-08-12 13:21:03 +02:00
lib lib/decompress_unlz4.c: correctly handle zero-padding around initrds. 2021-07-20 16:10:46 +02:00
mm mm: slab: fix kmem_cache_create failed when sysfs node not destroyed 2021-07-25 14:35:14 +02:00
net Bluetooth: defer cleanup of resources in hci_unregister_dev() 2021-08-12 13:20:58 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:53:30 +02:00
scripts scripts/tracing: fix the bug that can't parse raw_trace_func 2021-08-12 13:21:00 +02:00
security smackfs: restrict bytes count in smk_set_cipso() 2021-07-19 08:53:18 +02:00
sound ALSA: usb-audio: Add registration quirk for JBL Quantum 600 2021-08-12 13:20:59 +02:00
tools bpf, selftests: Adjust few selftest result_unpriv outcomes 2021-08-12 13:21:04 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Do not leak memory for duplicate debugfs directories 2021-08-12 13:21:03 +02:00
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.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
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MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.140 2021-08-12 13:21:05 +02:00
README

README

Linux kernel
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There are several guides for kernel developers and users. These guides can
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Please read the Documentation/process/changes.rst file, as it contains the
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