From 11ff753407ee7fd1cb2da06f8bedc5ac40ebbd95 Mon Sep 17 00:00:00 2001
From: Felix Held <felix-coreboot@felixheld.de>
Date: Tue, 6 Jun 2023 00:29:58 +0200
Subject: soc/amd/common/block/cpu/noncar: add
 get_usable_physical_address_bits()

In case the secure memory encryption is enabled, some of the upper
usable address bits of the host can't be used any more. Bits 11..6 in
CPUID_EBX_MEM_ENCRYPT indicate how many of the address bits are taken
away from the usable address bits in the case the secure memory
encryption is enabled.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ia810b0984972216095da2ad8f9c19e37684f2a2e
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75623
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
---
 src/soc/amd/common/block/cpu/noncar/cpu.c        | 18 ++++++++++++++++++
 src/soc/amd/common/block/include/amdblocks/cpu.h |  1 +
 2 files changed, 19 insertions(+)

(limited to 'src/soc')

diff --git a/src/soc/amd/common/block/cpu/noncar/cpu.c b/src/soc/amd/common/block/cpu/noncar/cpu.c
index 4afb69a299..891dece7dd 100644
--- a/src/soc/amd/common/block/cpu/noncar/cpu.c
+++ b/src/soc/amd/common/block/cpu/noncar/cpu.c
@@ -1,9 +1,12 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <amdblocks/cpu.h>
+#include <arch/cpuid.h>
 #include <cpu/cpu.h>
 #include <cpu/x86/msr.h>
+#include <cpu/amd/cpuid.h>
 #include <cpu/amd/msr.h>
+#include <cpu/amd/mtrr.h>
 #include <smbios.h>
 #include <soc/iomap.h>
 #include <types.h>
@@ -31,3 +34,18 @@ void set_cstate_io_addr(void)
 	cst_addr.lo = ACPI_CSTATE_CONTROL;
 	wrmsr(MSR_CSTATE_ADDRESS, cst_addr);
 }
+
+static uint32_t get_smee_reserved_address_bits(void)
+{
+	if (rdmsr(SYSCFG_MSR).raw & SYSCFG_MSR_SMEE)
+		return (cpuid_ebx(CPUID_EBX_MEM_ENCRYPT) &
+			CPUID_EBX_MEM_ENCRYPT_ADDR_BITS_MASK) >>
+			CPUID_EBX_MEM_ENCRYPT_ADDR_BITS_SHIFT;
+	else
+		return 0;
+}
+
+uint32_t get_usable_physical_address_bits(void)
+{
+	return cpu_phys_address_size() - get_smee_reserved_address_bits();
+}
diff --git a/src/soc/amd/common/block/include/amdblocks/cpu.h b/src/soc/amd/common/block/include/amdblocks/cpu.h
index 4aa225bda3..10dd23f11b 100644
--- a/src/soc/amd/common/block/include/amdblocks/cpu.h
+++ b/src/soc/amd/common/block/include/amdblocks/cpu.h
@@ -12,6 +12,7 @@ void early_cache_setup(void);
 int get_cpu_count(void);
 unsigned int get_threads_per_core(void);
 void set_cstate_io_addr(void);
+uint32_t get_usable_physical_address_bits(void);
 void write_resume_eip(void);
 
 union pstate_msr; /* proper definition is in soc/msr.h */
-- 
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