x86/cpu: Allow reducing x86_phys_bits during early_identify_cpu()

jira LE-2183
bug-fix x86/sev-es: Set x86_virt_bits
commit-author Paolo Bonzini <pbonzini@redhat.com>
commit 9a45819

In commit fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct
value straight away, instead of a two-phase approach"), the initialization
of c->x86_phys_bits was moved after this_cpu->c_early_init(c).  This is
incorrect because early_init_amd() expected to be able to reduce the
value according to the contents of CPUID leaf 0x8000001f.

Fortunately, the bug was negated by init_amd()'s call to early_init_amd(),
which does reduce x86_phys_bits in the end.  However, this is very
late in the boot process and, most notably, the wrong value is used for
x86_phys_bits when setting up MTRRs.

To fix this, call get_cpu_address_sizes() as soon as X86_FEATURE_CPUID is
set/cleared, and c->extended_cpuid_level is retrieved.

Fixes: fbf6449 ("x86/sev-es: Set x86_virt_bits to the correct value straight away, instead of a two-phase approach")
	Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
	Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
	Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240131230902.1867092-2-pbonzini%40redhat.com
(cherry picked from commit 9a45819)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>
Signed-off-by: Jonathan Maple <jmaple@ciq.com>
Signed-off-by: Shreeya Patel <spatel@ciq.com>

Author: PlaidCat

arch/x86/kernel/cpu/common.c

@@ -1494,6 +1494,7 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 		get_cpu_cap(c);
 		get_model_name(c); /* RHEL8: get model name for unsupported check */
 		setup_force_cpu_cap(X86_FEATURE_CPUID);
+		get_cpu_address_sizes(c);
 		cpu_parse_early_param();
 
 		if (this_cpu->c_early_init)
@@ -1507,10 +1508,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 	} else {
 		identify_cpu_without_cpuid(c);
 		setup_clear_cpu_cap(X86_FEATURE_CPUID);
+		get_cpu_address_sizes(c);
 	}
 
-	get_cpu_address_sizes(c);
-
 	setup_force_cpu_cap(X86_FEATURE_ALWAYS);
 
 	cpu_set_bug_bits(c);