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From:   "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        Jun Nakajima <jun.nakajima@intel.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "Kalra, Ashish" <ashish.kalra@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        "Huang, Kai" <kai.huang@intel.com>, Baoquan He <bhe@redhat.com>,
        kexec@lists.infradead.org, linux-coco@lists.linux.dev,
        linux-kernel@vger.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv2 06/13] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno
Date:   Fri, 20 Oct 2023 18:12:35 +0300
Message-ID: <20231020151242.1814-7-kirill.shutemov@linux.intel.com>
In-Reply-To: <20231020151242.1814-1-kirill.shutemov@linux.intel.com>
References: <20231020151242.1814-1-kirill.shutemov@linux.intel.com>
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TDX is going to have more than one reason to fail
enc_status_change_prepare().

Change the callback to return errno instead of assuming -EIO;
enc_status_change_finish() changed too to keep the interface symmetric.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/coco/tdx/tdx.c         | 20 +++++++++++---------
 arch/x86/hyperv/ivm.c           |  9 +++------
 arch/x86/include/asm/x86_init.h |  4 ++--
 arch/x86/kernel/x86_init.c      |  4 ++--
 arch/x86/mm/mem_encrypt_amd.c   |  8 ++++----
 arch/x86/mm/pat/set_memory.c    |  9 +++++----
 6 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index d11206ceff3b..8897d3cc8a15 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -776,28 +776,30 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
 	return true;
 }
 
-static bool tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
-					  bool enc)
+static int tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
+					 bool enc)
 {
 	/*
 	 * Only handle shared->private conversion here.
 	 * See the comment in tdx_early_init().
 	 */
-	if (enc)
-		return tdx_enc_status_changed(vaddr, numpages, enc);
-	return true;
+	if (enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+		return -EIO;
+
+	return 0;
 }
 
-static bool tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
+static int tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
 					 bool enc)
 {
 	/*
 	 * Only handle private->shared conversion here.
 	 * See the comment in tdx_early_init().
 	 */
-	if (!enc)
-		return tdx_enc_status_changed(vaddr, numpages, enc);
-	return true;
+	if (!enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+		return -EIO;
+
+	return 0;
 }
 
 void __init tdx_early_init(void)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index c1088d3661d5..7d2241059d49 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -510,13 +510,12 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
  * with host. This function works as wrap of hv_mark_gpa_visibility()
  * with memory base and size.
  */
-static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
+static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
 {
 	enum hv_mem_host_visibility visibility = enc ?
 			VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
 	u64 *pfn_array;
 	int ret = 0;
-	bool result = true;
 	int i, pfn;
 
 	pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
@@ -530,17 +529,15 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
 		if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
 			ret = hv_mark_gpa_visibility(pfn, pfn_array,
 						     visibility);
-			if (ret) {
-				result = false;
+			if (ret)
 				goto err_free_pfn_array;
-			}
 			pfn = 0;
 		}
 	}
 
  err_free_pfn_array:
 	kfree(pfn_array);
-	return result;
+	return ret;
 }
 
 static bool hv_vtom_tlb_flush_required(bool private)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 5240d88db52a..5031cbc6e211 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -150,8 +150,8 @@ struct x86_init_acpi {
  * @enc_cache_flush_required	Returns true if a cache flush is needed before changing page encryption status
  */
 struct x86_guest {
-	bool (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
-	bool (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
+	int (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
+	int (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
 	bool (*enc_tlb_flush_required)(bool enc);
 	bool (*enc_cache_flush_required)(void);
 };
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index a37ebd3b4773..f0f54e109eb9 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -131,8 +131,8 @@ struct x86_cpuinit_ops x86_cpuinit = {
 
 static void default_nmi_init(void) { };
 
-static bool enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return true; }
-static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return true; }
+static int enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
+static int enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
 static bool enc_tlb_flush_required_noop(bool enc) { return false; }
 static bool enc_cache_flush_required_noop(void) { return false; }
 static bool is_private_mmio_noop(u64 addr) {return false; }
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index a68f2dda0948..6cf6cc8ae6a6 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -282,7 +282,7 @@ static void enc_dec_hypercall(unsigned long vaddr, unsigned long size, bool enc)
 #endif
 }
 
-static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
 {
 	/*
 	 * To maintain the security guarantees of SEV-SNP guests, make sure
@@ -291,11 +291,11 @@ static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool
 	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !enc)
 		snp_set_memory_shared(vaddr, npages);
 
-	return true;
+	return 0;
 }
 
 /* Return true unconditionally: return value doesn't matter for the SEV side */
-static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
 {
 	/*
 	 * After memory is mapped encrypted in the page table, validate it
@@ -307,7 +307,7 @@ static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool e
 	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
 		enc_dec_hypercall(vaddr, npages << PAGE_SHIFT, enc);
 
-	return true;
+	return 0;
 }
 
 static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index bda9f129835e..6fbf22d5fa56 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2152,8 +2152,9 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
 		cpa_flush(&cpa, x86_platform.guest.enc_cache_flush_required());
 
 	/* Notify hypervisor that we are about to set/clr encryption attribute. */
-	if (!x86_platform.guest.enc_status_change_prepare(addr, numpages, enc))
-		return -EIO;
+	ret = x86_platform.guest.enc_status_change_prepare(addr, numpages, enc);
+	if (ret)
+		return ret;
 
 	ret = __change_page_attr_set_clr(&cpa, 1);
 
@@ -2168,8 +2169,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
 
 	/* Notify hypervisor that we have successfully set/clr encryption attribute. */
 	if (!ret) {
-		if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
-			ret = -EIO;
+		ret = x86_platform.guest.enc_status_change_finish(addr,
+								  numpages, enc);
 	}
 
 	return ret;
-- 
2.41.0