On 11/7/2023 10:55 PM, isaku.yamahata@xxxxxxxxx wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
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@xxxxxxxxx>
---
arch/x86/kvm/vmx/tdx_errno.h | 1 +
arch/x86/kvm/vmx/tdx_ops.h | 40 +++++++++++++++++++++---------------
2 files changed, 24 insertions(+), 17 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 12fd6b8d49e0..a55977626ae3 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>
@@ -17,25 +18,30 @@
static inline u64 tdx_seamcall(u64 op, u64 rcx, u64 rdx, u64 r8, u64 r9,
struct tdx_module_args *out)
{
+ int retry;
u64 ret;
- if (out) {
- *out = (struct tdx_module_args) {
- .rcx = rcx,
- .rdx = rdx,
- .r8 = r8,
- .r9 = r9,
- };
- ret = __seamcall_ret(op, out);
- } else {
- struct tdx_module_args args = {
- .rcx = rcx,
- .rdx = rdx,
- .r8 = r8,
- .r9 = r9,
- };
- ret = __seamcall(op, &args);
- }
+ /* Mimic the existing rdrand_long() to retry RDRAND_RETRY_LOOPS times. */
+ retry = RDRAND_RETRY_LOOPS;
Nit: The value can be assigned when define.
Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
+ do {
+ if (out) {
+ *out = (struct tdx_module_args) {
+ .rcx = rcx,
+ .rdx = rdx,
+ .r8 = r8,
+ .r9 = r9,
+ };
+ ret = __seamcall_ret(op, out);
+ } else {
+ struct tdx_module_args args = {
+ .rcx = rcx,
+ .rdx = rdx,
+ .r8 = r8,
+ .r9 = r9,
+ };
+ ret = __seamcall(op, &args);
+ }
+ } 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.
