From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Tom Lendacky <thomas.lendacky@amd.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 01/19] KVM: SVM: Fix off-by-one indexing when nullifying last used SEV VMCB
Date: Fri, 13 Aug 2021 17:07:18 +0200 [thread overview]
Message-ID: <20210813150522.671018477@linuxfoundation.org> (raw)
In-Reply-To: <20210813150522.623322501@linuxfoundation.org>
From: Sean Christopherson <seanjc@google.com>
[ 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
8a14fe4f0c54 ("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: 70cd94e60c73 ("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>
---
arch/x86/kvm/svm/sev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 01547bdbfb06..6c82ef22985d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -124,7 +124,7 @@ static void sev_asid_free(int asid)
for_each_possible_cpu(cpu) {
sd = per_cpu(svm_data, cpu);
- sd->sev_vmcbs[pos] = NULL;
+ sd->sev_vmcbs[asid] = NULL;
}
mutex_unlock(&sev_bitmap_lock);
--
2.30.2
next prev parent reply other threads:[~2021-08-13 15:17 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 15:07 [PATCH 5.10 00/19] 5.10.59-rc1 review Greg Kroah-Hartman
2021-08-13 15:07 ` Greg Kroah-Hartman [this message]
2021-08-13 15:07 ` [PATCH 5.10 02/19] tee: Correct inappropriate usage of TEE_SHM_DMA_BUF flag Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 03/19] firmware: tee_bnxt: Release TEE shm, session, and context during kexec Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 04/19] bpf: Add _kernel suffix to internal lockdown_bpf_read Greg Kroah-Hartman
2021-08-13 19:55 ` Pavel Machek
2021-08-13 21:57 ` Daniel Borkmann
2021-08-15 11:42 ` Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 05/19] bpf: Add lockdown check for probe_write_user helper Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 06/19] Revert "selftests/resctrl: Use resctrl/info for feature detection" Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 07/19] mm: make zone_to_nid() and zone_set_nid() available for DISCONTIGMEM Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 08/19] arm64: dts: renesas: rzg2: Add usb2_clksel to RZ/G2 M/N/H Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 09/19] arm64: dts: renesas: beacon: Fix USB extal reference Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 10/19] arm64: dts: renesas: beacon: Fix USB ref clock references Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 11/19] vboxsf: Honor excl flag to the dir-inode create op Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 12/19] vboxsf: Make vboxsf_dir_create() return the handle for the created file Greg Kroah-Hartman
2021-08-13 19:31 ` Pavel Machek
2021-08-15 11:43 ` Greg Kroah-Hartman
2021-08-15 13:57 ` Hans de Goede
2021-08-16 8:49 ` Greg Kroah-Hartman
2021-08-17 15:52 ` Sudip Mukherjee
2021-08-17 18:21 ` Hans de Goede
2021-08-13 15:07 ` [PATCH 5.10 13/19] USB:ehci:fix Kunpeng920 ehci hardware problem Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 14/19] ALSA: pcm: Fix mmap breakage without explicit buffer setup Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 15/19] ALSA: hda/realtek: fix mute/micmute LEDs for HP ProBook 650 G8 Notebook PC Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 16/19] ALSA: hda: Add quirk for ASUS Flow x13 Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 17/19] ppp: Fix generating ppp unit id when ifname is not specified Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 18/19] ovl: prevent private clone if bind mount is not allowed Greg Kroah-Hartman
2021-08-13 15:07 ` [PATCH 5.10 19/19] net: xilinx_emaclite: Do not print real IOMEM pointer Greg Kroah-Hartman
2021-08-13 23:24 ` [PATCH 5.10 00/19] 5.10.59-rc1 review Shuah Khan
2021-08-14 11:07 ` Sudip Mukherjee
2021-08-14 11:35 ` Naresh Kamboju
2021-08-14 15:08 ` Fox Chen
2021-08-14 18:16 ` Guenter Roeck
2021-08-15 19:48 ` Pavel Machek
2021-08-16 3:03 ` Samuel Zou
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210813150522.671018477@linuxfoundation.org \
--to=gregkh@linuxfoundation.org \
--cc=brijesh.singh@amd.com \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=sashal@kernel.org \
--cc=seanjc@google.com \
--cc=stable@vger.kernel.org \
--cc=thomas.lendacky@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).