On 4/5/22 21:49, Kai Huang wrote:
> TDX supports shutting down the TDX module at any time during its
> lifetime. After TDX module is shut down, no further SEAMCALL can be
> made on any logical cpu.
Is this strictly true?
I thought SEAMCALLs were used for the P-SEAMLDR too.
> Shut down the TDX module in case of any error happened during the
> initialization process. It's pointless to leave the TDX module in some
> middle state.
>
> Shutting down the TDX module requires calling TDH.SYS.LP.SHUTDOWN on all
> BIOS-enabled cpus, and the SEMACALL can run concurrently on different
> cpus. Implement a mechanism to run SEAMCALL concurrently on all online
> cpus. Logical-cpu scope initialization will use it too.
>
> Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
> ---
> arch/x86/virt/vmx/tdx/tdx.c | 40 ++++++++++++++++++++++++++++++++++++-
> arch/x86/virt/vmx/tdx/tdx.h | 5 +++++
> 2 files changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index 674867bccc14..faf8355965a5 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -11,6 +11,8 @@
> #include <linux/cpumask.h>
> #include <linux/mutex.h>
> #include <linux/cpu.h>
> +#include <linux/smp.h>
> +#include <linux/atomic.h>
> #include <asm/msr-index.h>
> #include <asm/msr.h>
> #include <asm/cpufeature.h>
> @@ -328,6 +330,39 @@ static int seamcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
> return 0;
> }
>
> +/* Data structure to make SEAMCALL on multiple CPUs concurrently */
> +struct seamcall_ctx {
> + u64 fn;
> + u64 rcx;
> + u64 rdx;
> + u64 r8;
> + u64 r9;
> + atomic_t err;
> + u64 seamcall_ret;
> + struct tdx_module_output out;
> +};
> +
> +static void seamcall_smp_call_function(void *data)
> +{
> + struct seamcall_ctx *sc = data;
> + int ret;
> +
> + ret = seamcall(sc->fn, sc->rcx, sc->rdx, sc->r8, sc->r9,
> + &sc->seamcall_ret, &sc->out);
> + if (ret)
> + atomic_set(&sc->err, ret);
> +}
> +
> +/*
> + * Call the SEAMCALL on all online cpus concurrently.
> + * Return error if SEAMCALL fails on any cpu.
> + */
> +static int seamcall_on_each_cpu(struct seamcall_ctx *sc)
> +{
> + on_each_cpu(seamcall_smp_call_function, sc, true);
> + return atomic_read(&sc->err);
> +}
Why bother returning something that's not read?
> static inline bool p_seamldr_ready(void)
> {
> return !!p_seamldr_info.p_seamldr_ready;
> @@ -437,7 +472,10 @@ static int init_tdx_module(void)
>
> static void shutdown_tdx_module(void)
> {
> - /* TODO: Shut down the TDX module */
> + struct seamcall_ctx sc = { .fn = TDH_SYS_LP_SHUTDOWN };
> +
> + seamcall_on_each_cpu(&sc);
> +
> tdx_module_status = TDX_MODULE_SHUTDOWN;
> }
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
> index 6990c93198b3..dcc1f6dfe378 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.h
> +++ b/arch/x86/virt/vmx/tdx/tdx.h
> @@ -35,6 +35,11 @@ struct p_seamldr_info {
> #define P_SEAMLDR_SEAMCALL_BASE BIT_ULL(63)
> #define P_SEAMCALL_SEAMLDR_INFO (P_SEAMLDR_SEAMCALL_BASE | 0x0)
>
> +/*
> + * TDX module SEAMCALL leaf functions
> + */
> +#define TDH_SYS_LP_SHUTDOWN 44
> +
> struct tdx_module_output;
> u64 __seamcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
> struct tdx_module_output *out);
