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From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	 Vitaly Kuznetsov <vkuznets@redhat.com>,
	David Woodhouse <dwmw2@infradead.org>,
	Paul Durrant <paul@xen.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	 Yosry Ahmed <yosry@kernel.org>,
	Binbin Wu <binbin.wu@linux.intel.com>,
	 David Woodhouse <dwmw@amazon.co.uk>,
	Kai Huang <kai.huang@intel.com>
Subject: [PATCH v3 09/40] KVM: x86: Drop non-raw kvm_<reg>_write() helpers
Date: Fri, 29 May 2026 15:21:52 -0700	[thread overview]
Message-ID: <20260529222223.870923-10-seanjc@google.com> (raw)
In-Reply-To: <20260529222223.870923-1-seanjc@google.com>

Drop the non-raw, mode-aware kvm_<reg>_write() helpers as there is no
usage in KVM, and in all likelihood there will never be usage in KVM as
use of hardcoded registers in instructions is uncommon, and *modifying*
hardcoded registers is practically unheard of.  While there are a few
instructions that modify registers in mode-aware ways, e.g. REP string
and some ENCLS varieties, the odds of KVM needing to emulate such
instructions (outside of the fully emulator) are vanishingly small.

Drop kvm_<reg>_write() to prevent incorrect usage; _if_ a new instruction
comes along that needs to modify a hardcoded register, this can be
reverted.

No functional change intended.

Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/regs.h | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/arch/x86/kvm/regs.h b/arch/x86/kvm/regs.h
index 12db5039aace..f22b3a8cd483 100644
--- a/arch/x86/kvm/regs.h
+++ b/arch/x86/kvm/regs.h
@@ -61,11 +61,6 @@ static __always_inline unsigned long kvm_##lname##_read(struct kvm_vcpu *vcpu)
 {											\
 	return vcpu->arch.regs[VCPU_REGS_##uname] & kvm_reg_mode_mask(vcpu);		\
 }											\
-static __always_inline void kvm_##lname##_write(struct kvm_vcpu *vcpu,			\
-						unsigned long val)			\
-{											\
-	vcpu->arch.regs[VCPU_REGS_##uname] = val & kvm_reg_mode_mask(vcpu);		\
-}											\
 static __always_inline unsigned long kvm_##lname##_read_raw(struct kvm_vcpu *vcpu)	\
 {											\
 	return vcpu->arch.regs[VCPU_REGS_##uname];					\
-- 
2.54.0.823.g6e5bcc1fc9-goog


  parent reply	other threads:[~2026-05-29 22:22 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-29 22:21 [PATCH v3 00/40] KVM: x86: GPR accessors and x86.{c,h} spring cleaning Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 01/40] KVM: SVM: Truncate INVLPGA address in compatibility mode Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 02/40] KVM: x86/xen: Bug the VM if 32-bit KVM observes a 64-bit mode hypercall Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 03/40] KVM: x86/xen: Don't truncate RAX when handling hypercall from protected guest Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 04/40] KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 05/40] KVM: x86: Trace hypercall register *after* truncating values for 32-bit Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 06/40] KVM: x86: Rename kvm_cache_regs.h => regs.h Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 07/40] KVM: x86: Move inlined GPR, CR, and DR helpers from x86.h to regs.h Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 08/40] KVM: x86: Add mode-aware versions of kvm_<reg>_{read,write}() helpers Sean Christopherson
2026-06-03 11:15   ` Huang, Kai
2026-05-29 22:21 ` Sean Christopherson [this message]
2026-05-29 22:21 ` [PATCH v3 10/40] KVM: nSVM: Use kvm_rax_read() now that it's mode-aware Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 11/40] Revert "KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode" Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 12/40] KVM: x86: Harden is_64_bit_hypercall() against bugs on 32-bit kernels Sean Christopherson
2026-05-29 22:21 ` [PATCH v3 13/40] KVM: x86: Move update_cr8_intercept() to lapic.c Sean Christopherson
2026-05-30  0:35   ` Yosry Ahmed
2026-06-03 11:16   ` Huang, Kai
2026-05-29 22:21 ` [PATCH v3 14/40] KVM: x86: Move async #PF helpers to x86.h (as inlines) Sean Christopherson
2026-05-30  0:36   ` Yosry Ahmed
2026-05-30  0:39     ` Sean Christopherson
2026-05-30  0:45       ` Yosry Ahmed
2026-06-03 11:18   ` Huang, Kai
2026-05-29 22:21 ` [PATCH v3 15/40] KVM: x86: Move the bulk of register specific code from x86.c to regs.c Sean Christopherson
2026-05-30  0:43   ` Yosry Ahmed
2026-06-01 14:15     ` Sean Christopherson
2026-06-01 23:35       ` Yosry Ahmed
2026-06-03 11:33   ` Huang, Kai
2026-05-29 22:21 ` [PATCH v3 16/40] KVM: x86: Move local APIC specific helpers out of asm/kvm_host.h Sean Christopherson
2026-05-30  0:37   ` Yosry Ahmed
2026-06-03 11:40   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 17/40] KVM: x86: Drop defunct vcpu_tsc_khz() declaration Sean Christopherson
2026-05-30  0:45   ` Yosry Ahmed
2026-06-03 11:41   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 18/40] KVM: x86: Move kvm_caps and kvm_host_values to asm/kvm_host.h Sean Christopherson
2026-05-30  0:46   ` Yosry Ahmed
2026-06-03 11:51   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 19/40] KVM: x86: Swap the include order between x86.h and mmu.h Sean Christopherson
2026-05-30  0:48   ` Yosry Ahmed
2026-06-01 14:55     ` Sean Christopherson
2026-06-01 20:27       ` Yosry Ahmed
2026-06-01 21:19         ` Sean Christopherson
2026-06-03 11:53   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 20/40] KVM: x86: Move tdp_enabled from kvm_host.h to mmu.h Sean Christopherson
2026-05-30  0:51   ` Yosry Ahmed
2026-06-03 11:56   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 21/40] KVM: x86: Move eager_page_split to mmu.{c,h} Sean Christopherson
2026-05-30  0:51   ` Yosry Ahmed
2026-06-03 11:59   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 22/40] KVM: x86/hyperv: Eliminate an unnecessary include of x86.h in hyperv.h Sean Christopherson
2026-06-04 11:00   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 23/40] KVM: x86: Move kvm_{load,put}_guest_fpu() to fpu.h Sean Christopherson
2026-05-30  0:52   ` Yosry Ahmed
2026-06-04 11:08   ` Huang, Kai
2026-06-05 19:14     ` Sean Christopherson
2026-05-29 22:22 ` [PATCH v3 24/40] KVM: x86: Extract get/set MSR (list) ioctl logic to helpers Sean Christopherson
2026-05-30  0:55   ` Yosry Ahmed
2026-06-04 11:18   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 25/40] KVM: x86: Expose several TSC helpers via x86.h for use by MSR code Sean Christopherson
2026-06-04 11:50   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 26/40] KVM: x86: Move the bulk of MSR specific code from x86.c to msrs.{c,h} Sean Christopherson
2026-06-04 12:03   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 27/40] KVM: x86: Move register helper declarations from kvm_host.h => regs.h Sean Christopherson
2026-05-30  0:56   ` Yosry Ahmed
2026-06-01 14:24     ` Sean Christopherson
2026-06-01 23:36       ` Yosry Ahmed
2026-06-04 12:38   ` Huang, Kai
2026-06-05 19:13     ` Sean Christopherson
2026-05-29 22:22 ` [PATCH v3 28/40] KVM: x86: Move kvm_{g,s}et_segment() to inline helpers in regs.h Sean Christopherson
2026-05-30  0:57   ` Yosry Ahmed
2026-06-04 12:39   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 29/40] KVM: x86: Remove defunct kvm_load_segment_descriptor() declaration Sean Christopherson
2026-05-30  0:57   ` Yosry Ahmed
2026-06-04 12:39   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 30/40] KVM: x86: Move MSR helper declarations from kvm_host.h => msrs.h Sean Christopherson
2026-05-30  0:59   ` Yosry Ahmed
2026-06-01 14:50     ` Sean Christopherson
2026-06-01 23:38       ` Yosry Ahmed
2026-06-05  6:53   ` Huang, Kai
2026-06-05 20:36     ` Sean Christopherson
2026-05-29 22:22 ` [PATCH v3 31/40] KVM: x86: Move MMU helper declarations from kvm_host.h => mmu.h Sean Christopherson
2026-05-30  0:59   ` Yosry Ahmed
2026-06-05  7:02   ` Huang, Kai
2026-06-05  7:50   ` Huang, Kai
2026-06-05 20:03     ` Sean Christopherson
2026-06-05 20:55       ` Sean Christopherson
2026-06-08 11:15         ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 32/40] KVM: x86: Move LLDT assembly wrappers into VMX Sean Christopherson
2026-05-30  1:02   ` Yosry Ahmed
2026-06-01 15:17     ` Sean Christopherson
2026-06-01 23:41       ` Yosry Ahmed
2026-05-29 22:22 ` [PATCH v3 33/40] KVM: x86: Move kvm_cpu_get_apicid() from kvm_host.h => avic.c Sean Christopherson
2026-05-30  1:03   ` Yosry Ahmed
2026-06-05  7:13   ` Huang, Kai
2026-06-05 20:29     ` Sean Christopherson
2026-05-29 22:22 ` [PATCH v3 34/40] KVM: x86: Move misc "VALID MASK" defines from kvm_host.h => x86.c Sean Christopherson
2026-05-30  1:05   ` Yosry Ahmed
2026-06-05  7:45   ` Huang, Kai
2026-06-05 20:32     ` Sean Christopherson
2026-06-08 11:17       ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 35/40] KVM: x86: Move __kvm_irq_line_state() from kvm_host.h => ioapic.h Sean Christopherson
2026-05-30  1:06   ` Yosry Ahmed
2026-06-05  7:53   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 36/40] KVM: x86: Move IRQ-related helper declarations from kvm_host.h => irq.h Sean Christopherson
2026-05-30  1:10   ` Yosry Ahmed
2026-06-01 15:22     ` Sean Christopherson
2026-06-01 23:44       ` Yosry Ahmed
2026-05-29 22:22 ` [PATCH v3 37/40] KVM: x86: Move kvm_pv_send_ipi() declaration from kvm_host.h => lapic.h Sean Christopherson
2026-05-30  1:11   ` Yosry Ahmed
2026-06-05  7:58   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 38/40] KVM: x86/mmu: Move kvm_arch_async_page_ready() below kvm_tdp_page_fault() Sean Christopherson
2026-05-30  1:12   ` Yosry Ahmed
2026-06-05  7:59   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 39/40] KVM: x86/mmu: Move kvm_mmu_do_page_fault() from mmu_internal.h => mmu.c Sean Christopherson
2026-05-30  1:13   ` Yosry Ahmed
2026-06-05  8:03   ` Huang, Kai
2026-05-29 22:22 ` [PATCH v3 40/40] KVM: x86: Move a pile of stuff from kvm_host.h => x86.h Sean Christopherson
2026-05-30 16:59 ` [PATCH v3 00/40] KVM: x86: GPR accessors and x86.{c,h} spring cleaning Paolo Bonzini
2026-06-03 12:58   ` Sean Christopherson
2026-06-05 18:31 ` Sean Christopherson

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