From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: Sasha Levin <sashal@kernel.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Leonardo Bras <leobras@redhat.com>,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org,
chang.seok.bae@intel.com, luto@kernel.org, kvm@vger.kernel.org,
Sean Christopherson <seanjc@google.com>
Subject: Re: [PATCH AUTOSEL 5.16 07/28] x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0
Date: Mon, 6 Jun 2022 18:18:12 +0200 [thread overview]
Message-ID: <2d9ba70b-ac18-a461-7a57-22df2c0165c6@redhat.com> (raw)
In-Reply-To: <YppVupW+IWsm7Osr@xz-m1.local>
On 6/3/22 20:40, Peter Xu wrote:
> I'm not really sure whether this is a bug or by design - do we require this
> patch to be applied to all stable branches to make the guest not crash
> after migration, or it is unexpected?
Yes, we do, though the only reported bug was for PKRU.
> However there seems to be something missing at least to me, on why it'll
> fail a migration from 5.15 (without this patch) to 5.18 (with this patch).
> In my test case, user_xfeatures will be 0x7 (FP|SSE|YMM) if without this
> patch, but 0x0 if with it.
What CPU model are you using for the VM? For example, if the source
lacks this patch but the destination has it, the source will transmit
YMM registers, but the destination will fail to set them if they are not
available for the selected CPU model.
See the commit message: "As a bonus, it will also fail if userspace
tries to set fpu features (with the KVM_SET_XSAVE ioctl) that are not
compatible to the guest configuration. Such features will never be
returned by KVM_GET_XSAVE or KVM_GET_XSAVE2."
Paolo
next prev parent reply other threads:[~2022-06-06 16:18 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-01 20:13 [PATCH AUTOSEL 5.16 01/28] selftests/bpf: Add test for bpf_timer overwriting crash Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 02/28] swiotlb: fix info leak with DMA_FROM_DEVICE Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 03/28] usb: dwc3: pci: add support for the Intel Raptor Lake-S Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 04/28] pinctrl: tigerlake: Revert "Add Alder Lake-M ACPI ID" Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 05/28] KVM: Fix lockdep false negative during host resume Sasha Levin
2022-03-01 20:19 ` Paolo Bonzini
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 06/28] kvm: x86: Disable KVM_HC_CLOCK_PAIRING if tsc is in always catchup mode Sasha Levin
2022-03-01 20:19 ` Paolo Bonzini
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 07/28] x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0 Sasha Levin
2022-03-01 20:22 ` Paolo Bonzini
2022-06-03 18:40 ` Peter Xu
2022-06-06 16:18 ` Paolo Bonzini [this message]
2022-06-06 21:27 ` Peter Xu
2022-06-07 12:54 ` Paolo Bonzini
2022-06-07 15:04 ` Sean Christopherson
2022-06-07 18:17 ` Peter Xu
2022-06-07 18:47 ` Sean Christopherson
2022-06-07 21:01 ` Peter Xu
2022-06-07 18:55 ` Peter Xu
2022-06-08 20:34 ` Leonardo Bras Soares Passos
2022-06-08 20:53 ` Peter Xu
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 08/28] spi: rockchip: Fix error in getting num-cs property Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 09/28] spi: rockchip: terminate dma transmission when slave abort Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 10/28] drm/vc4: hdmi: Unregister codec device on unbind Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 11/28] of/fdt: move elfcorehdr reservation early for crash dump kernel Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 12/28] x86/kvm: Don't use pv tlb/ipi/sched_yield if on 1 vCPU Sasha Levin
2022-03-01 20:17 ` Paolo Bonzini
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 13/28] drivers: hamradio: 6pack: fix UAF bug caused by mod_timer() Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 14/28] net-sysfs: add check for netdevice being present to speed_show Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 15/28] sr9700: sanity check for packet length Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 16/28] hwmon: (pmbus) Clear pmbus fault/warning bits after read Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 17/28] nvme-tcp: send H2CData PDUs based on MAXH2CDATA Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 18/28] PCI: Mark all AMD Navi10 and Navi14 GPU ATS as broken Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 19/28] gpio: Return EPROBE_DEFER if gc->to_irq is NULL Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 20/28] drm/amdgpu: bypass tiling flag check in virtual display case (v2) Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 21/28] Revert "xen-netback: remove 'hotplug-status' once it has served its purpose" Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 22/28] Revert "xen-netback: Check for hotplug-status existence before watching" Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 23/28] ipv6: prevent a possible race condition with lifetimes Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 24/28] tracing: Ensure trace buffer is at least 4096 bytes large Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 25/28] tracing/osnoise: Make osnoise_main to sleep for microseconds Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 26/28] tracing: Fix selftest config check for function graph start up test Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 27/28] selftest/vm: fix map_fixed_noreplace test failure Sasha Levin
2022-03-01 20:13 ` [PATCH AUTOSEL 5.16 28/28] selftests/memfd: clean up mapping in mfd_fail_write Sasha Levin
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