From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Jim Mattson <jmattson@google.com>
Cc: <pbonzini@redhat.com>, <seanjc@google.com>, <kvm@vger.kernel.org>,
<x86@kernel.org>, <linux-kernel@vger.kernel.org>,
<zhao1.liu@intel.com>
Subject: Re: [PATCH v8 03/20] KVM: x86: Support APX state for XSAVE ABI
Date: Thu, 5 Nov 2026 21:57:07 -0800 [thread overview]
Message-ID: <4b8e0f1b-266c-490c-8a95-008d936d0d6a@intel.com> (raw)
In-Reply-To: <CALMp9eQOkFJrzN_ws-CKLj5BaDhXgLbHGDF9g6t8_gNTQvsU2A@mail.gmail.com>
On 11/5/2026 9:46 PM, Jim Mattson wrote:
>
> Look at the lines immediately preceding the ones you quoted in
> copy_uabi_to_xstate():
>
> /*
> * The state that came in from userspace was user-state only.
> * Mask all the user states out of 'xfeatures':
> */
> xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL;
>
> /*
> * Add back in the features that came in from userspace:
> */
> xsave->header.xfeatures |= hdr.xfeatures;
>
> All user-state bits in xsave->header.xfeatures are cleared before
> hdr.xfeatures is ORed in. If userspace clears bit i for any user state
> component in hdr.xfeatures, bit i in xsave->header.xfeatures is cleared,
> and the component is reset to its initial state.
Ah, right. Looks like sticking to what I thought before...
next prev parent reply other threads:[~2026-11-06 5:57 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-30 21:07 [PATCH v8 00/20] KVM: x86: Enable APX for guests Chang S. Bae
2026-09-30 21:07 ` [PATCH v8 01/20] KVM: x86: Extend VCPU registers for EGPRs Chang S. Bae
2026-11-05 23:42 ` Jim Mattson
2026-11-06 5:32 ` Chang S. Bae
2026-09-30 21:07 ` [PATCH v8 02/20] KVM: VMX: Save guest EGPRs in VCPU cache Chang S. Bae
2026-11-05 23:52 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 03/20] KVM: x86: Support APX state for XSAVE ABI Chang S. Bae
2026-11-06 0:13 ` Jim Mattson
2026-11-06 5:33 ` Chang S. Bae
2026-11-06 5:46 ` Jim Mattson
2026-11-06 5:57 ` Chang S. Bae [this message]
2026-09-30 21:07 ` [PATCH v8 04/20] KVM: VMX: Refactor VMX instruction information access Chang S. Bae
2026-11-06 0:17 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 05/20] KVM: VMX: Refactor instruction information decoding Chang S. Bae
2026-11-06 0:19 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 06/20] KVM: VMX: Remove unused control-register access defines Chang S. Bae
2026-11-06 0:20 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 07/20] KVM: VMX: Refactor register index retrieval from exit qualification Chang S. Bae
2026-11-06 0:22 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 08/20] KVM: VMX: Support instruction information extension Chang S. Bae
2026-11-06 0:40 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 09/20] KVM: nVMX: Propagate extended instruction information Chang S. Bae
2026-11-06 0:53 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 10/20] KVM: x86: Support EGPR accessing and tracking for emulator Chang S. Bae
2026-11-06 0:55 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 11/20] KVM: x86: Handle EGPR index and REX2-incompatible opcodes Chang S. Bae
2026-11-06 4:34 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 12/20] KVM: x86: Support REX2-prefixed opcode decode Chang S. Bae
2026-11-06 4:48 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 13/20] KVM: x86: Reject EVEX-prefixed instructions Chang S. Bae
2026-11-06 4:56 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 14/20] KVM: x86: Move KVM_SUPPORTED_{XCR0,XSS} into kvm_x86_vendor_init() Chang S. Bae
2026-11-06 4:58 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 15/20] KVM: x86: Guard valid XCR0.APX settings Chang S. Bae
2026-11-06 5:00 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 16/20] KVM: x86: Add APX to supported XCR0 Chang S. Bae
2026-11-06 5:01 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 17/20] KVM: x86: Expose APX foundation feature to userspace Chang S. Bae
2026-11-06 5:05 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 18/20] KVM: x86: Expose APX sub-features " Chang S. Bae
2026-09-30 21:07 ` [PATCH v8 19/20] KVM: x86: selftests: Add APX state and ABI test Chang S. Bae
2026-11-06 5:31 ` Jim Mattson
2026-09-30 21:07 ` [PATCH v8 20/20] KVM: x86: selftests: Add APX state handling and XCR0 sanity checks Chang S. Bae
2026-11-06 5:36 ` Jim Mattson
2026-10-01 20:29 ` [PATCH v8 00/20] KVM: x86: Enable APX for guests Chang S. Bae
2026-11-04 0:45 ` Chang S. Bae
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