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i386/tdx: Validate phys_bits against host value

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For TDX guest, the phys_bits is not configurable and can only be
host/native value.

Validate phys_bits inside tdx_check_features().

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-55-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Xiaoyao Li 2025-05-08 11:00:00 -04:00 • committed by Paolo Bonzini
parent ea4867b911
commit 907ee7b67e
3 changed files with 10 additions and 1 deletions
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2
target/i386/host-cpu.c
View file

@ -15,7 +15,7 @@
#include "system/system.h"
/* Note: Only safe for use on x86(-64) hosts */
static uint32_t host_cpu_phys_bits(void)
uint32_t host_cpu_phys_bits(void)
{
uint32_t eax;
uint32_t host_phys_bits;

1
target/i386/host-cpu.h
View file

@ -10,6 +10,7 @@
#ifndef HOST_CPU_H
#define HOST_CPU_H
uint32_t host_cpu_phys_bits(void);
void host_cpu_instance_init(X86CPU *cpu);
void host_cpu_max_instance_init(X86CPU *cpu);
bool host_cpu_realizefn(CPUState *cs, Error **errp);

8
target/i386/kvm/tdx.c
View file

@ -25,6 +25,7 @@
#include "cpu.h"
#include "cpu-internal.h"
#include "host-cpu.h"
#include "hw/i386/e820_memory_layout.h"
#include "hw/i386/tdvf.h"
#include "hw/i386/x86.h"
@ -879,6 +880,13 @@ static int tdx_check_features(X86ConfidentialGuest *cg, CPUState *cs)
return -EINVAL;
}
if (cpu->phys_bits != host_cpu_phys_bits()) {
error_report("TDX requires guest CPU physical bits (%u) "
"to match host CPU physical bits (%u)",
cpu->phys_bits, host_cpu_phys_bits());
return -EINVAL;
}
return 0;
}