Re: [RFC PATCH v4 14/28] Add support to access boot related data in the clear

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On 3/8/2017 12:55 AM, Dave Young wrote:
On 02/16/17 at 09:45am, Tom Lendacky wrote:
[snip]
+ * This function determines if an address should be mapped encrypted.
+ * Boot setup data, EFI data and E820 areas are checked in making this
+ * determination.
+ */
+static bool memremap_should_map_encrypted(resource_size_t phys_addr,
+					  unsigned long size)
+{
+	/*
+	 * SME is not active, return true:
+	 *   - For early_memremap_pgprot_adjust(), returning true or false
+	 *     results in the same protection value
+	 *   - For arch_memremap_do_ram_remap(), returning true will allow
+	 *     the RAM remap to occur instead of falling back to ioremap()
+	 */
+	if (!sme_active())
+		return true;

From the function name shouldn't above be return false?

I've re-worked this so that the check is in a different location and
doesn't cause confusion.


+
+	/* Check if the address is part of the setup data */
+	if (memremap_is_setup_data(phys_addr, size))
+		return false;
+
+	/* Check if the address is part of EFI boot/runtime data */
+	switch (efi_mem_type(phys_addr)) {
+	case EFI_BOOT_SERVICES_DATA:
+	case EFI_RUNTIME_SERVICES_DATA:

Only these two types needed? I'm not sure about this, just bring up the
question.

I've re-worked this code so that there is a single EFI routine that
checks boot_params.efi_info.efi_memmap/efi_systab, EFI tables and the
EFI memtype.  As for the EFI memtypes, I believe those are the only
ones required.  Some of the other types will be picked up by the e820
checks (ACPI, NVS, etc.).

Thanks,
Tom


+		return false;
+	default:
+		break;
+	}
+
+	/* Check if the address is outside kernel usable area */
+	switch (e820__get_entry_type(phys_addr, phys_addr + size - 1)) {
+	case E820_TYPE_RESERVED:
+	case E820_TYPE_ACPI:
+	case E820_TYPE_NVS:
+	case E820_TYPE_UNUSABLE:
+		return false;
+	default:
+		break;
+	}
+
+	return true;
+}
+

Thanks
Dave

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