From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Kiryl Shutsemau <kas@kernel.org>,
David Woodhouse <dwmw2@infradead.org>,
Paul Durrant <paul@xen.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
kvm@vger.kernel.org, x86@kernel.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org, Yosry Ahmed <yosry@kernel.org>,
Kai Huang <kai.huang@intel.com>,
Binbin Wu <binbin.wu@linux.intel.com>
Subject: [PATCH v2 09/15] KVM: x86: Drop non-raw kvm_<reg>_write() helpers
Date: Thu, 14 May 2026 14:53:49 -0700 [thread overview]
Message-ID: <20260514215355.1648463-10-seanjc@google.com> (raw)
In-Reply-To: <20260514215355.1648463-1-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.
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 b28e71caed25..52bed14f43e3 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]; \
--
2.54.0.563.g4f69b47b94-goog
next prev parent reply other threads:[~2026-05-14 21:54 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-14 21:53 [PATCH v2 00/15] KVM: x86: Clean up kvm_<reg>_{read,write}() mess Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 01/15] KVM: SVM: Truncate INVLPGA address in compatibility mode Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 02/15] KVM: x86/xen: Bug the VM if 32-bit KVM observes a 64-bit mode hypercall Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 03/15] KVM: x86/xen: Don't truncate RAX when handling hypercall from protected guest Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 04/15] KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 05/15] KVM: x86: Trace hypercall register *after* truncating values for 32-bit Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 06/15] KVM: x86: Rename kvm_cache_regs.h => regs.h Sean Christopherson
2026-05-14 22:28 ` Yosry Ahmed
2026-05-14 21:53 ` [PATCH v2 07/15] KVM: x86: Move inlined CR and DR helpers from x86.h to regs.h Sean Christopherson
2026-05-14 22:30 ` Yosry Ahmed
2026-05-14 21:53 ` [PATCH v2 08/15] KVM: x86: Add mode-aware versions of kvm_<reg>_{read,write}() helpers Sean Christopherson
2026-05-14 21:53 ` Sean Christopherson [this message]
2026-05-14 21:53 ` [PATCH v2 10/15] KVM: nSVM: Use kvm_rax_read() now that it's mode-aware Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 11/15] Revert "KVM: VMX: Read 32-bit GPR values for ENCLS instructions outside of 64-bit mode" Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 12/15] KVM: x86: Harden is_64_bit_hypercall() against bugs on 32-bit kernels Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 13/15] KVM: x86: Move update_cr8_intercept() to lapic.c Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 14/15] KVM: x86: Move kvm_pv_async_pf_enabled() to x86.h (as an inline) Sean Christopherson
2026-05-14 21:53 ` [PATCH v2 15/15] KVM: x86: Move the bulk of register specific code from x86.c to regs.c Sean Christopherson
2026-05-14 22:31 ` [PATCH v2 00/15] KVM: x86: Clean up kvm_<reg>_{read,write}() mess Yosry Ahmed
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=20260514215355.1648463-10-seanjc@google.com \
--to=seanjc@google.com \
--cc=binbin.wu@linux.intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=dwmw2@infradead.org \
--cc=kai.huang@intel.com \
--cc=kas@kernel.org \
--cc=kvm@vger.kernel.org \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=paul@xen.org \
--cc=pbonzini@redhat.com \
--cc=rick.p.edgecombe@intel.com \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
--cc=yosry@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