From: Paolo Bonzini <pbonzini@redhat.com>
To: Sasha Levin <sashal@kernel.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>, kvm@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.3 28/68] KVM: x86: Expose XSAVEERPTR to the guest
Date: Wed, 9 Oct 2019 23:15:07 +0200 [thread overview]
Message-ID: <05acd554-dd0a-d7cd-e17c-90627fa0ec67@redhat.com> (raw)
In-Reply-To: <20191009170547.32204-28-sashal@kernel.org>
On 09/10/19 19:05, Sasha Levin wrote:
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>
> [ Upstream commit 504ce1954fba888936c9d13ccc1e3db9b8f613d5 ]
>
> I was surprised to see that the guest reported `fxsave_leak' while the
> host did not. After digging deeper I noticed that the bits are simply
> masked out during enumeration.
>
> The XSAVEERPTR feature is actually a bug fix on AMD which means the
> kernel can disable a workaround.
>
> Pass XSAVEERPTR to the guest if available on the host.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> arch/x86/kvm/cpuid.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index fd1b8db8bf242..59b66e343fa5a 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -479,6 +479,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
>
> /* cpuid 0x80000008.ebx */
> const u32 kvm_cpuid_8000_0008_ebx_x86_features =
> + F(XSAVEERPTR) |
> F(WBNOINVD) | F(AMD_IBPB) | F(AMD_IBRS) | F(AMD_SSBD) | F(VIRT_SSBD) |
> F(AMD_SSB_NO) | F(AMD_STIBP) | F(AMD_STIBP_ALWAYS_ON);
>
>
Yet another example of a patch that shouldn't be stable material (in
this case it's fine, but there can certainly be cases where just adding
a single flag depends on core kernel changes).
Paolo
next prev parent reply other threads:[~2019-10-09 21:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 17:04 [PATCH AUTOSEL 5.3 01/68] KVM: arm/arm64: vgic: Use the appropriate TRACE_INCLUDE_PATH Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 02/68] drm: Free the writeback_job when it with an empty fb Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 03/68] drm: Clear the fence pointer when writeback job signaled Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 04/68] clk: ti: dra7: Fix mcasp8 clock bits Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 05/68] ARM: dts: Fix wrong clocks for dra7 mcasp Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 06/68] nvme-pci: Fix a race in controller removal Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 07/68] scsi: ufs: skip shutdown if hba is not powered Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 08/68] scsi: megaraid: disable device when probe failed after enabled device Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 09/68] scsi: qla2xxx: Silence fwdump template message Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 10/68] scsi: qla2xxx: Fix unbound sleep in fcport delete path Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 11/68] scsi: qla2xxx: Fix stale mem access on driver unload Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 12/68] scsi: qla2xxx: Fix N2N link reset Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 13/68] scsi: qla2xxx: Fix N2N link up fail Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 14/68] ARM: dts: Fix gpio0 flags for am335x-icev2 Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 15/68] ARM: OMAP2+: Fix missing reset done flag for am3 and am43 Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 16/68] ARM: OMAP2+: Add missing LCDC midlemode for am335x Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 17/68] ARM: OMAP2+: Fix warnings with broken omap2_set_init_voltage() Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 18/68] nvme-tcp: fix wrong stop condition in io_work Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 19/68] nvme-pci: Save PCI state before putting drive into deepest state Sasha Levin
2019-10-09 17:04 ` [PATCH AUTOSEL 5.3 20/68] nvme: fix an error code in nvme_init_subsystem() Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 21/68] nvme-rdma: Fix max_hw_sectors calculation Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 22/68] Added QUIRKs for ADATA XPG SX8200 Pro 512GB Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 23/68] nvme: Add quirk for Kingston NVME SSD running FW E8FK11.T Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 24/68] nvme: allow 64-bit results in passthru commands Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 25/68] kvm: x86: Fix a spurious -E2BIG in __do_cpuid_func Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 26/68] kvm: x86: Improve emulation of CPUID leaves 0BH and 1FH Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 27/68] kvm: x86: Use AMD CPUID semantics for AMD vCPUs Sasha Levin
2019-10-09 17:05 ` [PATCH AUTOSEL 5.3 28/68] KVM: x86: Expose XSAVEERPTR to the guest Sasha Levin
2019-10-09 21:15 ` Paolo Bonzini [this message]
2019-10-09 21:40 ` Sebastian Andrzej Siewior
2019-10-09 22:50 ` Paolo Bonzini
2019-10-10 7:35 ` Sebastian Andrzej Siewior
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=05acd554-dd0a-d7cd-e17c-90627fa0ec67@redhat.com \
--to=pbonzini@redhat.com \
--cc=bigeasy@linutronix.de \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sashal@kernel.org \
--cc=stable@vger.kernel.org \
/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).