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22 Feb 2024 19:21:59 -0800 Date: Fri, 23 Feb 2024 11:35:39 +0800 From: Zhao Liu To: Binbin Wu Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, pbonzini@redhat.com, xiaoyao.li@intel.com, chao.gao@intel.com, robert.hu@linux.intel.com Subject: Re: [PATCH v4 2/2] target/i386: add control bits support for LAM Message-ID: References: <20240112060042.19925-1-binbin.wu@linux.intel.com> <20240112060042.19925-3-binbin.wu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240112060042.19925-3-binbin.wu@linux.intel.com> Received-SPF: pass client-ip=198.175.65.17; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.002, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Jan 12, 2024 at 02:00:42PM +0800, Binbin Wu wrote: > Date: Fri, 12 Jan 2024 14:00:42 +0800 > From: Binbin Wu > Subject: [PATCH v4 2/2] target/i386: add control bits support for LAM > X-Mailer: git-send-email 2.25.1 > > 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 > Tested-by: Xuelian Guo > --- > target/i386/cpu.h | 7 ++++++- > target/i386/helper.c | 4 ++++ > 2 files changed, 10 insertions(+), 1 deletion(-) Reviewed-by: Zhao Liu > > 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.c > index 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; > > -- > 2.25.1 > >