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From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: <pbonzini@redhat.com>, <kvm@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <chao.gao@intel.com>
Subject: Re: [PATCH v2 01/16] KVM: x86: Rename register accessors to be GPR-specific
Date: Tue, 10 Mar 2026 15:05:20 -0700	[thread overview]
Message-ID: <31093743-97e2-42a7-a989-84704f25f40e@intel.com> (raw)
In-Reply-To: <aa9ym-SWeOdTrz0O@google.com>

On 3/9/2026 6:23 PM, Sean Christopherson wrote:
> 
> Oh, yikes, I didn't even see that this series is playing games with the register
> indices.
> 
> Whatever we do, the changelog asbolutely needs to call out the real motiviation.

Given the discussion here, it looks so apparent the changelog is missing 
that detail. I'll ensure something like what you wrote here to the revision.

> I'll try to come back to this tomorrow with more complete thoughts and hopefully

Sure, you call it. I know you have a lot on your plate, so I hope you 
feel free to take your time. Thanks!

> E.g. passing in VCPU_REGS_RIP to kvm_gpr_read() will compile just fine, but will
> read the wrong register on APX capable hardware.

Right, so new semantics likely need to be established. As responded 
before, one option would be separate them in structure:

diff --git a/arch/x86/include/asm/kvm_host.h 
b/arch/x86/include/asm/kvm_host.h
index ff07c45e3c73..ff8a317be5cf 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -795,10 +795,14 @@ enum kvm_only_cpuid_leafs {

  struct kvm_vcpu_arch {
         /*
-        * rip and regs accesses must go through
-        * kvm_{register,rip}_{read,write} functions.
+        * regs accesses must go through kvm_register_{read,write}
+        * functions.
          */
         unsigned long regs[NR_VCPU_REGS];
+
+       /* rip accesses must go through kvm_rip_{read,write} */
+       unsigned long rip;
+
         u32 regs_avail;
         u32 regs_dirty;

  reply	other threads:[~2026-03-10 22:05 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-12 23:53 [PATCH v2 00/16] KVM: x86: Enable APX for guests Chang S. Bae
2026-01-12 23:53 ` [PATCH v2 01/16] KVM: x86: Rename register accessors to be GPR-specific Chang S. Bae
2026-03-05  1:35   ` Sean Christopherson
2026-03-07  1:32     ` Chang S. Bae
2026-03-09 23:28       ` Chang S. Bae
2026-03-10  1:23       ` Sean Christopherson
2026-03-10 22:05         ` Chang S. Bae [this message]
2026-03-10 23:12           ` Sean Christopherson
2026-01-12 23:53 ` [PATCH v2 02/16] KVM: x86: Refactor GPR accessors to differentiate register access types Chang S. Bae
2026-03-05  1:49   ` Sean Christopherson
2026-03-07  1:32     ` Chang S. Bae
2026-01-12 23:53 ` [PATCH v2 03/16] KVM: x86: Implement accessors for extended GPRs Chang S. Bae
2026-03-05  1:41   ` Sean Christopherson
2026-03-07  1:32     ` Chang S. Bae
2026-01-12 23:53 ` [PATCH v2 04/16] KVM: VMX: Introduce unified instruction info structure Chang S. Bae
2026-03-05  4:21   ` Sean Christopherson
2026-03-07  1:33     ` Chang S. Bae
2026-03-13  1:05       ` Sean Christopherson
2026-01-12 23:53 ` [PATCH v2 05/16] KVM: VMX: Refactor instruction information retrieval Chang S. Bae
2026-01-12 23:53 ` [PATCH v2 06/16] KVM: VMX: Refactor GPR index retrieval from exit qualification Chang S. Bae
2026-03-05  4:13   ` Sean Christopherson
2026-01-12 23:53 ` [PATCH v2 07/16] KVM: VMX: Support extended register index in exit handling Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 08/16] KVM: nVMX: Propagate the extended instruction info field Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 09/16] KVM: emulate: Support EGPR accessing and tracking Chang S. Bae
2026-03-05  4:22   ` Sean Christopherson
2026-01-12 23:54 ` [PATCH v2 10/16] KVM: emulate: Handle EGPR index and REX2-incompatible opcodes Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 11/16] KVM: emulate: Support REX2-prefixed opcode decode Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 12/16] KVM: emulate: Reject EVEX-prefixed instructions Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 13/16] KVM: x86: Guard valid XCR0.APX settings Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 14/16] KVM: x86: Expose APX foundational feature bit to guests Chang S. Bae
2026-01-19  5:55   ` Xiaoyao Li
2026-01-20 18:07     ` Edgecombe, Rick P
2026-01-20 20:50       ` Chang S. Bae
2026-01-21 19:59         ` Edgecombe, Rick P
2026-01-12 23:54 ` [PATCH v2 15/16] KVM: x86: Expose APX sub-features " Chang S. Bae
2026-01-12 23:54 ` [PATCH v2 16/16] KVM: x86: selftests: Add APX state handling and XCR0 sanity checks Chang S. Bae
2026-03-05  4:28   ` Sean Christopherson
2026-03-07  1:33     ` Chang S. Bae
2026-03-11 18:42       ` Paolo Bonzini
2026-04-20 21:23         ` [PATCH kvm-unit-tests] x86: xsave: Add test case for emulation of APX instructions Chang S. Bae

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