From ed302854d0155e24a3620b92e7e9f591d510c252 Mon Sep 17 00:00:00 2001 From: Xiaoyao Li Date: Thu, 17 Jul 2025 10:20:09 +0800 Subject: [PATCH] KVM: TDX: Don't report base TDVMCALLs Remove TDVMCALLINFO_GET_QUOTE from user_tdvmcallinfo_1_r11 reported to userspace to align with the direction of the GHCI spec. Recently, concern was raised about a gap in the GHCI spec that left ambiguity in how to expose to the guest that only a subset of GHCI TDVMCalls were supported. During the back and forth on the spec details[0], was moved from an individually enumerable TDVMCall, to one that is part of the 'base spec', meaning it doesn't have a specific bit in the return values. Although the spec[1] is still in draft form, the GetQoute part has been agreed by the major TDX VMMs. Unfortunately the commits that were upstreamed still treat as individually enumerable. They set bit 0 in the user_tdvmcallinfo_1_r11 which is reported to userspace to tell supported optional TDVMCalls, intending to say that is supported. So stop reporting in user_tdvmcallinfo_1_r11 to align with the direction of the spec, and allow some future TDVMCall to use that bit. [0] https://lore.kernel.org/all/aEmuKII8FGU4eQZz@google.com/ [1] https://cdrdv2.intel.com/v1/dl/getContent/858626 Fixes: 28224ef02b56 ("KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities") Signed-off-by: Xiaoyao Li Message-ID: <20250717022010.677645-1-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/tdx.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index f31ccdeb905b4..ea1261ca805fe 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -173,7 +173,6 @@ static void td_init_cpuid_entry2(struct kvm_cpuid_entry2 *entry, unsigned char i tdx_clear_unsupported_cpuid(entry); } -#define TDVMCALLINFO_GET_QUOTE BIT(0) #define TDVMCALLINFO_SETUP_EVENT_NOTIFY_INTERRUPT BIT(1) static int init_kvm_tdx_caps(const struct tdx_sys_info_td_conf *td_conf, @@ -192,7 +191,6 @@ static int init_kvm_tdx_caps(const struct tdx_sys_info_td_conf *td_conf, caps->cpuid.nent = td_conf->num_cpuid_config; caps->user_tdvmcallinfo_1_r11 = - TDVMCALLINFO_GET_QUOTE | TDVMCALLINFO_SETUP_EVENT_NOTIFY_INTERRUPT; for (i = 0; i < td_conf->num_cpuid_config; i++) -- 2.47.2