| Message ID | a4d44b01523c935595c8ee00622ab8766e269ef4.1705965634.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM TDX basic feature support | expand |
On 1/23/2024 7:52 AM, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Some SEAMCALL may return TDX_RND_NO_ENTROPY error when the entropy is > lacking. Retry SEAMCALL on the error following rdrand_long() to retry > RDRAND_RETRY_LOOPS times. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > v18: > - update to use struct tdx_modules_args for inputs. > --- > arch/x86/kvm/vmx/tdx_errno.h | 1 + > arch/x86/kvm/vmx/tdx_ops.h | 15 +++++++++++---- > 2 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/vmx/tdx_errno.h b/arch/x86/kvm/vmx/tdx_errno.h > index 7f96696b8e7c..bb093e292fef 100644 > --- a/arch/x86/kvm/vmx/tdx_errno.h > +++ b/arch/x86/kvm/vmx/tdx_errno.h > @@ -14,6 +14,7 @@ > #define TDX_OPERAND_INVALID 0xC000010000000000ULL > #define TDX_OPERAND_BUSY 0x8000020000000000ULL > #define TDX_PREVIOUS_TLB_EPOCH_BUSY 0x8000020100000000ULL > +#define TDX_RND_NO_ENTROPY 0x8000020300000000ULL > #define TDX_VCPU_NOT_ASSOCIATED 0x8000070200000000ULL > #define TDX_KEY_GENERATION_FAILED 0x8000080000000000ULL > #define TDX_KEY_STATE_INCORRECT 0xC000081100000000ULL > diff --git a/arch/x86/kvm/vmx/tdx_ops.h b/arch/x86/kvm/vmx/tdx_ops.h > index 0e26cf22240e..f4c16e5265f0 100644 > --- a/arch/x86/kvm/vmx/tdx_ops.h > +++ b/arch/x86/kvm/vmx/tdx_ops.h > @@ -6,6 +6,7 @@ > > #include <linux/compiler.h> > > +#include <asm/archrandom.h> > #include <asm/cacheflush.h> > #include <asm/asm.h> > #include <asm/kvm_host.h> > @@ -17,14 +18,20 @@ > static inline u64 tdx_seamcall(u64 op, struct tdx_module_args *in, > struct tdx_module_args *out) > { > + struct tdx_module_args args; > + int retry; > u64 ret; > > - if (out) { > + if (!out) > + out = &args; > + > + /* Mimic the existing rdrand_long() to retry RDRAND_RETRY_LOOPS times. */ > + retry = RDRAND_RETRY_LOOPS; > + do { > + /* As __seamcall_ret() overwrites out, init out on each loop. */ > *out = *in; > ret = __seamcall_ret(op, out); > - } else > - ret = __seamcall(op, in); > - > + } while (unlikely(ret == TDX_RND_NO_ENTROPY) && --retry); > if (unlikely(ret == TDX_SEAMCALL_UD)) { > /* > * SEAMCALLs fail with TDX_SEAMCALL_UD returned when VMX is off. One question is when the return code is TDX_RND_NO_ENTROPY, does the input tdx_module_args value will be modified or not? As mentioned by Kai in previous review, there are seamcall*() variants which handle TDX_RND_NO_ENTROPY already. If the input tdx_module_args is not modified by a seamcall when the return code is TDX_RND_NO_ENTROPY, the seamcall_ret() can be used directly. But if the input tdx_module_args could be modified by a seamcall when the return code is TDX_RND_NO_ENTROPY, the implementations of seamcall_ret() and seamcall_saved_ret() have problem then, because the input tdx_module_args is not re-initialized when retry. They need to be fixed or deleted (no one is using them currently).
On Tue, Jan 23, 2024 at 12:55 AM <isaku.yamahata@intel.com> wrote: > > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Some SEAMCALL may return TDX_RND_NO_ENTROPY error when the entropy is > lacking. Retry SEAMCALL on the error following rdrand_long() to retry > RDRAND_RETRY_LOOPS times. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> This patch should not be needed anymore, just... > + /* Mimic the existing rdrand_long() to retry RDRAND_RETRY_LOOPS times. */ > + retry = RDRAND_RETRY_LOOPS; > + do { > + /* As __seamcall_ret() overwrites out, init out on each loop. */ > *out = *in; > ret = __seamcall_ret(op, out); > - } else > - ret = __seamcall(op, in); ... use seamcall() and seamcall_ret() here instead of the "__" versions. Paolo
diff --git a/arch/x86/kvm/vmx/tdx_errno.h b/arch/x86/kvm/vmx/tdx_errno.h index 7f96696b8e7c..bb093e292fef 100644 --- a/arch/x86/kvm/vmx/tdx_errno.h +++ b/arch/x86/kvm/vmx/tdx_errno.h @@ -14,6 +14,7 @@ #define TDX_OPERAND_INVALID 0xC000010000000000ULL #define TDX_OPERAND_BUSY 0x8000020000000000ULL #define TDX_PREVIOUS_TLB_EPOCH_BUSY 0x8000020100000000ULL +#define TDX_RND_NO_ENTROPY 0x8000020300000000ULL #define TDX_VCPU_NOT_ASSOCIATED 0x8000070200000000ULL #define TDX_KEY_GENERATION_FAILED 0x8000080000000000ULL #define TDX_KEY_STATE_INCORRECT 0xC000081100000000ULL diff --git a/arch/x86/kvm/vmx/tdx_ops.h b/arch/x86/kvm/vmx/tdx_ops.h index 0e26cf22240e..f4c16e5265f0 100644 --- a/arch/x86/kvm/vmx/tdx_ops.h +++ b/arch/x86/kvm/vmx/tdx_ops.h @@ -6,6 +6,7 @@ #include <linux/compiler.h> +#include <asm/archrandom.h> #include <asm/cacheflush.h> #include <asm/asm.h> #include <asm/kvm_host.h> @@ -17,14 +18,20 @@ static inline u64 tdx_seamcall(u64 op, struct tdx_module_args *in, struct tdx_module_args *out) { + struct tdx_module_args args; + int retry; u64 ret; - if (out) { + if (!out) + out = &args; + + /* Mimic the existing rdrand_long() to retry RDRAND_RETRY_LOOPS times. */ + retry = RDRAND_RETRY_LOOPS; + do { + /* As __seamcall_ret() overwrites out, init out on each loop. */ *out = *in; ret = __seamcall_ret(op, out); - } else - ret = __seamcall(op, in); - + } while (unlikely(ret == TDX_RND_NO_ENTROPY) && --retry); if (unlikely(ret == TDX_SEAMCALL_UD)) { /* * SEAMCALLs fail with TDX_SEAMCALL_UD returned when VMX is off.