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From: Kuppuswamy Sathyanarayanan  <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>
Cc: Peter H Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kirill Shutemov <kirill.shutemov@linux.intel.com>,
	Sean Christopherson <seanjc@google.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 06/10] x86/insn-eval: Introduce insn_get_modrm_reg_ptr()
Date: Wed,  4 Aug 2021 12:18:51 -0700	[thread overview]
Message-ID: <20210804191855.2901927-7-sathyanarayanan.kuppuswamy@linux.intel.com> (raw)
In-Reply-To: <20210804191855.2901927-1-sathyanarayanan.kuppuswamy@linux.intel.com>

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

The helper returns a pointer to the register indicated by
ModRM byte.

It's going to replace vc_insn_get_reg() in the SEV MMIO
implementation. TDX MMIO implementation will also use it.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---

Changes since v3:
 * None

Changes since v2:
 * None

 arch/x86/include/asm/insn-eval.h |  1 +
 arch/x86/lib/insn-eval.c         | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index 91d7182ad2d6..041f399153b9 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h
@@ -19,6 +19,7 @@ bool insn_has_rep_prefix(struct insn *insn);
 void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
 int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
 int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs);
+void *insn_get_modrm_reg_ptr(struct insn *insn, struct pt_regs *regs);
 unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx);
 int insn_get_code_seg_params(struct pt_regs *regs);
 int insn_fetch_from_user(struct pt_regs *regs,
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index a1d24fdc07cf..fbaa3fa24bde 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -850,6 +850,26 @@ int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs)
 	return get_reg_offset(insn, regs, REG_TYPE_REG);
 }
 
+/**
+ * insn_get_modrm_reg_ptr() - Obtain register pointer based on ModRM byte
+ * @insn:	Instruction containing the ModRM byte
+ * @regs:	Register values as seen when entering kernel mode
+ *
+ * Returns:
+ *
+ * The register indicated by the reg part of the ModRM byte.
+ * The register is obtained as a pointer within pt_regs.
+ */
+void *insn_get_modrm_reg_ptr(struct insn *insn, struct pt_regs *regs)
+{
+	int offset;
+
+	offset = insn_get_modrm_reg_off(insn, regs);
+	if (offset < 0)
+		return NULL;
+	return (void *)regs + offset;
+}
+
 /**
  * get_seg_base_limit() - obtain base address and limit of a segment
  * @insn:	Instruction. Must be valid.
-- 
2.25.1


  parent reply	other threads:[~2021-08-04 19:19 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04 19:18 [PATCH v4 00/10] Add TDX Guest Support (#VE handler support) Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 01/10] x86/io: Allow to override inX() and outX() implementation Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 02/10] x86/tdx: Add early_is_tdx_guest() interface Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 03/10] x86/tdx: Handle port I/O in decompression code Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 04/10] x86/tdx: Handle early IO operations Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 05/10] x86/tdx: Handle port I/O Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` Kuppuswamy Sathyanarayanan [this message]
2021-08-04 19:18 ` [PATCH v4 07/10] x86/insn-eval: Introduce insn_decode_mmio() Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 08/10] x86/sev-es: Use insn_decode_mmio() for MMIO implementation Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 09/10] x86/tdx: Handle in-kernel MMIO Kuppuswamy Sathyanarayanan
2021-08-04 19:18 ` [PATCH v4 10/10] x86/tdx: Handle MWAIT and MONITOR Kuppuswamy Sathyanarayanan

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