From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shuai Ruan Subject: [PATCH 3/3] x86/xsaves: ebx may return wrong value using CPUID eax=0xdh, ecx =1 Date: Mon, 22 Feb 2016 13:35:21 +0800 Message-ID: <1456119321-10384-4-git-send-email-shuai.ruan@linux.intel.com> References: <1456119321-10384-1-git-send-email-shuai.ruan@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1456119321-10384-1-git-send-email-shuai.ruan@linux.intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: wei.liu2@citrix.com, Ian.Campbell@citrix.com, stefano.stabellini@eu.citrix.com, andrew.cooper3@citrix.com, ian.jackson@eu.citrix.com, jbeulich@suse.com, keir@xen.org List-Id: xen-devel@lists.xenproject.org Refer to SDM 13.4.3 Extended Region of an XSAVE Area. The value return by ecx[1] with cpuid function 0xdh and sub-fucntion i (i>1) indicates the alignment of the state component i when the compacted format of the extended region of an xsave area is used. So when hvm guest using CPUID eax=0xdh,ecx=1 to get the size of area used for compacted format, we need to take alignment into consideration. Signed-off-by: Shuai Ruan --- tools/libxc/xc_cpuid_x86.c | 10 ++++++++-- xen/arch/x86/hvm/hvm.c | 12 ++++++++++++ 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c index c142595..d36f20b 100644 --- a/tools/libxc/xc_cpuid_x86.c +++ b/tools/libxc/xc_cpuid_x86.c @@ -285,6 +285,7 @@ static void intel_xc_cpuid_policy(xc_interface *xch, #define XSAVEC (1 << 1) #define XGETBV1 (1 << 2) #define XSAVES (1 << 3) +#define XSTATE_ALIGN64 (1 << 1) /* Configure extended state enumeration leaves (0x0000000D for xsave) */ static void xc_cpuid_config_xsave(xc_interface *xch, const struct cpuid_domain_info *info, @@ -333,8 +334,13 @@ static void xc_cpuid_config_xsave(xc_interface *xch, regs[0] = regs[1] = regs[2] = regs[3] = 0; break; } - /* Don't touch EAX, EBX. Also cleanup ECX and EDX */ - regs[2] = regs[3] = 0; + /* Don't touch EAX, EBX. + * ECX[1] indicates whether the state component + * needs alignment when compacted format is used. + */ + regs[2] &= XSTATE_ALIGN64; + /* Clean up EDX */ + regs[3] = 0; break; } } diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index fe382ce..4ccd392 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -4703,7 +4703,19 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx, for ( sub_leaf = 2; sub_leaf < 63; sub_leaf++ ) if ( (v->arch.xcr0 | v->arch.hvm_vcpu.msr_xss) & (1ULL << sub_leaf) ) + { + domain_cpuid(d, input, sub_leaf, &_eax, &_ebx, + &_ecx, &_edx); + /* + * The value return by _ecx[1] indicates the + * alignment of the state component i when the + * compacted format of the extended region of + * an xsave area is used. + */ + if (_ecx & XSTATE_ALIGN64) + *ebx = ROUNDUP(*ebx, 64); *ebx += xstate_sizes[sub_leaf]; + } } else *ebx = *ecx = *edx = 0; -- 1.9.1