linux-kernel - [PATCH v2 2/2] x86/boot: Add setup_indirect support in early_memremap_is_setup

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Message-Id: <1645668456-22036-3-git-send-email-ross.philipson@oracle.com>
Date:   Wed, 23 Feb 2022 21:07:36 -0500
From:   Ross Philipson <ross.philipson@...cle.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     ross.philipson@...cle.com, daniel.kiper@...cle.com,
        dpsmith@...rtussolutions.com, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, hpa@...or.com, luto@...capital.net,
        dave.hansen@...ux.intel.com, kanth.ghatraju@...cle.com,
        trenchboot-devel@...glegroups.com
Subject: [PATCH v2 2/2] x86/boot: Add setup_indirect support in early_memremap_is_setup_data

The x86 boot documentation describes the setup_indirect structures and
how they are used. Only one of the two functions in ioremap.c that needed
to be modified to be aware of the introduction of setup_indirect
functionality was updated. Adds comparable support to the other function
where it was missing.

Fixes: b3c72fc9a78e ("x86/boot: Introduce setup_indirect")
Signed-off-by: Ross Philipson <ross.philipson@...cle.com>
---
 arch/x86/mm/ioremap.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index ab666c4..17a492c 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -676,22 +676,51 @@ static bool memremap_is_setup_data(resource_size_t phys_addr,
 static bool __init early_memremap_is_setup_data(resource_size_t phys_addr,
 						unsigned long size)
 {
+	struct setup_indirect *indirect;
 	struct setup_data *data;
 	u64 paddr, paddr_next;
 
 	paddr = boot_params.hdr.setup_data;
 	while (paddr) {
-		unsigned int len;
+		unsigned int len, size;
 
 		if (phys_addr == paddr)
 			return true;
 
 		data = early_memremap_decrypted(paddr, sizeof(*data));
+		if (!data) {
+			pr_warn("failed to early memremap setup_data entry\n");
+			return false;
+		}
+
+		size = sizeof(*data);
 
 		paddr_next = data->next;
 		len = data->len;
 
-		early_memunmap(data, sizeof(*data));
+		if ((phys_addr > paddr) && (phys_addr < (paddr + len))) {
+			early_memunmap(data, sizeof(*data));
+			return true;
+		}
+
+		if (data->type == SETUP_INDIRECT) {
+			size += len;
+			early_memunmap(data, sizeof(*data));
+			data = early_memremap_decrypted(paddr, size);
+			if (!data) {
+				pr_warn("failed to early memremap indirect setup_data\n");
+				return false;
+			}
+
+			indirect = (struct setup_indirect *)data->data;
+
+			if (indirect->type != SETUP_INDIRECT) {
+				paddr = indirect->addr;
+				len = indirect->len;
+			}
+		}
+
+		early_memunmap(data, size);
 
 		if ((phys_addr > paddr) && (phys_addr < (paddr + len)))
 			return true;
-- 
1.8.3.1