On Fri, Jan 24, 2025 at 2:40 PM Xiaoyao Li <xiaoyao.li@xxxxxxxxx> wrote:
>
> For TDX guest, the phys_bits is not configurable and can only be
> host/native value.
>
> Validate phys_bits inside tdx_check_features().
Hi Xiaoyao,
to avoid
qemu-kvm: TDX requires guest CPU physical bits (48) to match host CPU
physical bits (52)
I need options like
-cpu host,phys-bits=52,guest-phys-bits=52,host-phys-bits-limit=52,-kvm-asyncpf-int
to start a TDX guest, is that intentional?
Thanks,
Paolo
> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> ---
> target/i386/host-cpu.c | 2 +-
> target/i386/host-cpu.h | 1 +
> target/i386/kvm/tdx.c | 8 ++++++++
> 3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/target/i386/host-cpu.c b/target/i386/host-cpu.c
> index 3e4e85e729c8..8a15af458b05 100644
> --- a/target/i386/host-cpu.c
> +++ b/target/i386/host-cpu.c
> @@ -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;
> diff --git a/target/i386/host-cpu.h b/target/i386/host-cpu.h
> index 6a9bc918baa4..b97ec01c9bec 100644
> --- a/target/i386/host-cpu.h
> +++ b/target/i386/host-cpu.h
> @@ -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);
> diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
> index bb75eb06dad9..c906a76c4c0e 100644
> --- a/target/i386/kvm/tdx.c
> +++ b/target/i386/kvm/tdx.c
> @@ -24,6 +24,7 @@
>
> #include "cpu.h"
> #include "cpu-internal.h"
> +#include "host-cpu.h"
> #include "hw/i386/e820_memory_layout.h"
> #include "hw/i386/x86.h"
> #include "hw/i386/tdvf.h"
> @@ -838,6 +839,13 @@ static int tdx_check_features(X86ConfidentialGuest *cg, CPUState *cs)
> return -1;
> }
>
> + 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());
> + exit(1);
> + }
> +
> return 0;
> }
>
> --
> 2.34.1
>
