x86/cpu: Prevent cpuinfo_x86::x86_phys_bits adjustment corruption (d94a155c) · Commits · 戴 / test

Some features (Intel MKTME, AMD SME) reduce the number of effectively available physical address bits. cpuinfo_x86::x86_phys_bits is adjusted accordingly during the early cpu feature detection. Though if get_cpu_cap() is called later again then this adjustement is overwritten. That happens in setup_pku(), which is called after detect_tme(). To address this, extract the address sizes enumeration into a separate function, which is only called only from early_identify_cpu() and from generic_identify(). This makes get_cpu_cap() safe to be called later during boot proccess without overwriting cpuinfo_x86::x86_phys_bits. [ tglx: Massaged changelog ] Fixes: ("x86/tme: Detect if TME and MKTME is activated by BIOS") Reported-by:

Kai Huang <kai.huang@linux.intel.com> Signed-off-by:

Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: linux-mm@kvack.org Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/20180410092704.41106-1-kirill.shutemov@linux.intel.com

arch/x86/kernel/cpu/common.c

+20 −12

Original line number	Diff line number	Diff line
		@@ -848,18 +848,6 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
		c->x86_power = edx;
		}

		if (c->extended_cpuid_level >= 0x80000008) {
		cpuid(0x80000008, &eax, &ebx, &ecx, &edx);

		c->x86_virt_bits = (eax >> 8) & 0xff;
		c->x86_phys_bits = eax & 0xff;
		c->x86_capability[CPUID_8000_0008_EBX] = ebx;
		}
		#ifdef CONFIG_X86_32
		else if (cpu_has(c, X86_FEATURE_PAE) \|\| cpu_has(c, X86_FEATURE_PSE36))
		c->x86_phys_bits = 36;
		#endif

		if (c->extended_cpuid_level >= 0x8000000a)
		c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);

		@@ -874,6 +862,23 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
		apply_forced_caps(c);
		}

		static void get_cpu_address_sizes(struct cpuinfo_x86 *c)
		{
		u32 eax, ebx, ecx, edx;

		if (c->extended_cpuid_level >= 0x80000008) {
		cpuid(0x80000008, &eax, &ebx, &ecx, &edx);

		c->x86_virt_bits = (eax >> 8) & 0xff;
		c->x86_phys_bits = eax & 0xff;
		c->x86_capability[CPUID_8000_0008_EBX] = ebx;
		}
		#ifdef CONFIG_X86_32
		else if (cpu_has(c, X86_FEATURE_PAE) \|\| cpu_has(c, X86_FEATURE_PSE36))
		c->x86_phys_bits = 36;
		#endif
		}

		static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
		{
		#ifdef CONFIG_X86_32
		@@ -965,6 +970,7 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
		cpu_detect(c);
		get_cpu_vendor(c);
		get_cpu_cap(c);
		get_cpu_address_sizes(c);
		setup_force_cpu_cap(X86_FEATURE_CPUID);

		if (this_cpu->c_early_init)
		@@ -1097,6 +1103,8 @@ static void generic_identify(struct cpuinfo_x86 *c)

		get_cpu_cap(c);

		get_cpu_address_sizes(c);

		if (c->cpuid_level >= 0x00000001) {
		c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
		#ifdef CONFIG_X86_32

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