linux-kernel - [PATCH RFC v1 09/20] KVM: x86: Support EGPR accessing and tracking for instruction emulation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251110180131.28264-10-chang.seok.bae@intel.com>
Date: Mon, 10 Nov 2025 18:01:20 +0000
From: "Chang S. Bae" <chang.seok.bae@...el.com>
To: kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: pbonzini@...hat.com,
	seanjc@...gle.com,
	chao.gao@...el.com,
	zhao1.liu@...el.com,
	chang.seok.bae@...el.com
Subject: [PATCH RFC v1 09/20] KVM: x86: Support EGPR accessing and tracking for instruction emulation

Extend the emulator context and GPR accessors to handle EGPRs before
adding support for REX2-prefixed instructions.

Now the KVM GPR accessors can handle EGPRs. Then, the emulator can
uniformly cache and track all GPRs without requiring separate handling.

Signed-off-by: Chang S. Bae <chang.seok.bae@...el.com>
---
 arch/x86/kvm/kvm_emulate.h | 10 +++++-----
 arch/x86/kvm/x86.c         |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 7b5ddb787a25..153c70ea5561 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -105,13 +105,13 @@ struct x86_instruction_info {
 struct x86_emulate_ops {
 	void (*vm_bugged)(struct x86_emulate_ctxt *ctxt);
 	/*
-	 * read_gpr: read a general purpose register (rax - r15)
+	 * read_gpr: read a general purpose register (rax - r31)
 	 *
 	 * @reg: gpr number.
 	 */
 	ulong (*read_gpr)(struct x86_emulate_ctxt *ctxt, unsigned reg);
 	/*
-	 * write_gpr: write a general purpose register (rax - r15)
+	 * write_gpr: write a general purpose register (rax - r31)
 	 *
 	 * @reg: gpr number.
 	 * @val: value to write.
@@ -312,7 +312,7 @@ typedef void (*fastop_t)(struct fastop *);
  * a ModRM or SIB byte.
  */
 #ifdef CONFIG_X86_64
-#define NR_EMULATOR_GPRS	16
+#define NR_EMULATOR_GPRS	32
 #else
 #define NR_EMULATOR_GPRS	8
 #endif
@@ -361,9 +361,9 @@ struct x86_emulate_ctxt {
 	u8 lock_prefix;
 	u8 rep_prefix;
 	/* bitmaps of registers in _regs[] that can be read */
-	u16 regs_valid;
+	u32 regs_valid;
 	/* bitmaps of registers in _regs[] that have been written */
-	u16 regs_dirty;
+	u32 regs_dirty;
 	/* modrm */
 	u8 modrm;
 	u8 modrm_mod;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 603057ea7421..338986a5a3ae 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8812,12 +8812,12 @@ static bool emulator_guest_cpuid_is_intel_compatible(struct x86_emulate_ctxt *ct
 
 static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg)
 {
-	return kvm_register_read_raw(emul_to_vcpu(ctxt), reg);
+	return _kvm_gpr_read(emul_to_vcpu(ctxt), reg);
 }
 
 static void emulator_write_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val)
 {
-	kvm_register_write_raw(emul_to_vcpu(ctxt), reg, val);
+	_kvm_gpr_write(emul_to_vcpu(ctxt), reg, val);
 }
 
 static void emulator_set_nmi_mask(struct x86_emulate_ctxt *ctxt, bool masked)
-- 
2.51.0