[RFC PATCH 06/11] x86/mm: Add generic guest initialization hook

From: Nikunj A Dadhania <nikunj@amd.com>
To: <linux-kernel@vger.kernel.org>, <x86@kernel.org>
Cc: <bp@alien8.de>, <thomas.lendacky@amd.com>,
	<dionnaglaze@google.com>, <pgonda@google.com>, <jroedel@suse.de>,
	<mingo@redhat.com>, <tglx@linutronix.de>,
	<dave.hansen@linux.intel.com>, <seanjc@google.com>,
	<pbonzini@redhat.com>, <nikunj@amd.com>, <michael.roth@amd.com>,
	<ketanch@iitk.ac.in>
Subject: [RFC PATCH 06/11] x86/mm: Add generic guest initialization hook
Date: Mon, 30 Jan 2023 17:33:22 +0530	[thread overview]
Message-ID: <20230130120327.977460-7-nikunj@amd.com> (raw)
In-Reply-To: <20230130120327.977460-1-nikunj@amd.com>

Add generic enc_init guest hook for performing any type of
initialization that is vendor specific.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
 arch/x86/include/asm/x86_init.h | 2 ++
 arch/x86/kernel/x86_init.c      | 2 ++
 arch/x86/mm/mem_encrypt.c       | 3 +++
 3 files changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index c1c8c581759d..4026ac30a79f 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -148,12 +148,14 @@ struct x86_init_acpi {
  * @enc_status_change_finish	Notify HV after the encryption status of a range is changed
  * @enc_tlb_flush_required	Returns true if a TLB flush is needed before changing page encryption status
  * @enc_cache_flush_required	Returns true if a cache flush is needed before changing page encryption status
+ * @enc_init			Prepare and initialize encryption features
  */
 struct x86_guest {
 	void (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
 	bool (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
 	bool (*enc_tlb_flush_required)(bool enc);
 	bool (*enc_cache_flush_required)(void);
+	void (*enc_init)(void);
 };
 
 /**
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index ef80d361b463..a71996e51a9c 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -134,6 +134,7 @@ static void enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool
 static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return false; }
 static bool enc_tlb_flush_required_noop(bool enc) { return false; }
 static bool enc_cache_flush_required_noop(void) { return false; }
+static void enc_init_noop(void) { }
 
 struct x86_platform_ops x86_platform __ro_after_init = {
 	.calibrate_cpu			= native_calibrate_cpu_early,
@@ -155,6 +156,7 @@ struct x86_platform_ops x86_platform __ro_after_init = {
 		.enc_status_change_finish  = enc_status_change_finish_noop,
 		.enc_tlb_flush_required	   = enc_tlb_flush_required_noop,
 		.enc_cache_flush_required  = enc_cache_flush_required_noop,
+		.enc_init		   = enc_init_noop,
 	},
 };
 
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 9f27e14e185f..01abecc9a774 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -84,5 +84,8 @@ void __init mem_encrypt_init(void)
 	/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
 	swiotlb_update_mem_attributes();
 
+	if (x86_platform.guest.enc_init)
+		x86_platform.guest.enc_init();
+
 	print_mem_encrypt_feature_info();
 }
-- 
2.32.0

