On 1/12/2024 2:00 PM, Binbin Wu wrote:
LAM uses CR3[61] and CR3[62] to configure/enable LAM on user pointers. LAM uses CR4[28] to configure/enable LAM on supervisor pointers. For CR3 LAM bits, no additional handling needed: - TCG LAM is not supported for TCG of target-i386. helper_write_crN() and helper_vmrun() check max physical address bits before calling cpu_x86_update_cr3(), no change needed, i.e. CR3 LAM bits are not allowed to be set in TCG. - gdbstub x86_cpu_gdb_write_register() will call cpu_x86_update_cr3() to update cr3. Allow gdb to set the LAM bit(s) to CR3, if vcpu doesn't support LAM, KVM_SET_SREGS will fail as other reserved bits. For CR4 LAM bit, its reservation depends on vcpu supporting LAM feature or not. - TCG LAM is not supported for TCG of target-i386. helper_write_crN() and helper_vmrun() check CR4 reserved bit before calling cpu_x86_update_cr4(), i.e. CR4 LAM bit is not allowed to be set in TCG. - gdbstub x86_cpu_gdb_write_register() will call cpu_x86_update_cr4() to update cr4. Mask out LAM bit on CR4 if vcpu doesn't support LAM. - x86_cpu_reset_hold() doesn't need special handling. Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> Tested-by: Xuelian Guo <xuelian.guo@xxxxxxxxx>
Reviewed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
--- target/i386/cpu.h | 7 ++++++- target/i386/helper.c | 4 ++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 18ea755644..598a3fa140 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -261,6 +261,7 @@ typedef enum X86Seg { #define CR4_SMAP_MASK (1U << 21) #define CR4_PKE_MASK (1U << 22) #define CR4_PKS_MASK (1U << 24) +#define CR4_LAM_SUP_MASK (1U << 28)#define CR4_RESERVED_MASK \(~(target_ulong)(CR4_VME_MASK | CR4_PVI_MASK | CR4_TSD_MASK \ @@ -269,7 +270,8 @@ typedef enum X86Seg { | CR4_OSFXSR_MASK | CR4_OSXMMEXCPT_MASK | CR4_UMIP_MASK \ | CR4_LA57_MASK \ | CR4_FSGSBASE_MASK | CR4_PCIDE_MASK | CR4_OSXSAVE_MASK \ - | CR4_SMEP_MASK | CR4_SMAP_MASK | CR4_PKE_MASK | CR4_PKS_MASK)) + | CR4_SMEP_MASK | CR4_SMAP_MASK | CR4_PKE_MASK | CR4_PKS_MASK \ + | CR4_LAM_SUP_MASK))#define DR6_BD (1 << 13)#define DR6_BS (1 << 14) @@ -2522,6 +2524,9 @@ static inline uint64_t cr4_reserved_bits(CPUX86State *env) if (!(env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_PKS)) { reserved_bits |= CR4_PKS_MASK; } + if (!(env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_LAM)) { + reserved_bits |= CR4_LAM_SUP_MASK; + } return reserved_bits; }diff --git a/target/i386/helper.c b/target/i386/helper.cindex 2070dd0dda..1da7a7d315 100644 --- a/target/i386/helper.c +++ b/target/i386/helper.c @@ -219,6 +219,10 @@ void cpu_x86_update_cr4(CPUX86State *env, uint32_t new_cr4) new_cr4 &= ~CR4_PKS_MASK; }+ if (!(env->features[FEAT_7_1_EAX] & CPUID_7_1_EAX_LAM)) {+ new_cr4 &= ~CR4_LAM_SUP_MASK; + } + env->cr[4] = new_cr4; env->hflags = hflags;
