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[Xen-devel] [PATCH v2 10/25] x86/hvm: Improve CR4 verification using named features

From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Date: Mon, 9 Jan 2017 11:03:27 +0000

Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Delivery-date: Mon, 09 Jan 2017 11:16:27 +0000

List-id: Xen developer discussion <xen-devel.lists.xen.org>

Alter the function to return the valid CR4 bits, rather than the invalid CR4 bits. This will allow reuse in other areas of code. Pick the appropriate cpuid_policy object rather than using hvm_cpuid() or boot_cpu_data. This breaks the dependency on current. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> --- xen/arch/x86/domain.c | 2 +- xen/arch/x86/hvm/hvm.c | 92 +++++++++++++++---------------------------- xen/include/asm-x86/hvm/hvm.h | 2 +- 3 files changed, 34 insertions(+), 62 deletions(-) diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c index b554a9c..319cc8a 100644 --- a/xen/arch/x86/domain.c +++ b/xen/arch/x86/domain.c @@ -1512,7 +1512,7 @@ int arch_set_info_hvm_guest(struct vcpu *v, const vcpu_hvm_context_t *ctx) if ( v->arch.hvm_vcpu.guest_efer & EFER_LME ) v->arch.hvm_vcpu.guest_efer |= EFER_LMA; - if ( v->arch.hvm_vcpu.guest_cr[4] & hvm_cr4_guest_reserved_bits(v, 0) ) + if ( v->arch.hvm_vcpu.guest_cr[4] & ~hvm_cr4_guest_valid_bits(v, 0) ) { gprintk(XENLOG_ERR, "Bad CR4 value: %#016lx\n", v->arch.hvm_vcpu.guest_cr[4]); diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index a9daf40..4ecdb35 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -957,67 +957,39 @@ const char *hvm_efer_valid(const struct vcpu *v, uint64_t value, X86_CR0_WP | X86_CR0_AM | X86_CR0_NW | \ X86_CR0_CD | X86_CR0_PG))) -/* These bits in CR4 cannot be set by the guest. */ -unsigned long hvm_cr4_guest_reserved_bits(const struct vcpu *v,bool_t restore) +/* These bits in CR4 can be set by the guest. */ +unsigned long hvm_cr4_guest_valid_bits(const struct vcpu *v, bool restore) { - unsigned int leaf1_ecx = 0, leaf1_edx = 0; - unsigned int leaf7_0_ebx = 0, leaf7_0_ecx = 0; - - if ( !restore && !is_hardware_domain(v->domain) ) - { - unsigned int level; + const struct domain *d = v->domain; + const struct cpuid_policy *p; + bool mce, vmxe; - ASSERT(v->domain == current->domain); - hvm_cpuid(0, &level, NULL, NULL, NULL); - if ( level >= 1 ) - hvm_cpuid(1, NULL, NULL, &leaf1_ecx, &leaf1_edx); - if ( level >= 7 ) - hvm_cpuid(7, NULL, &leaf7_0_ebx, &leaf7_0_ecx, NULL); - } + if ( !restore && !is_hardware_domain(d) ) + p = d->arch.cpuid; else - { - leaf1_edx = boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_VME)]; - leaf1_ecx = boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_PCID)]; - leaf7_0_ebx = boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_FSGSBASE)]; - leaf7_0_ecx = boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_PKU)]; - } - - return ~(unsigned long) - ((leaf1_edx & cpufeat_mask(X86_FEATURE_VME) ? - X86_CR4_VME | X86_CR4_PVI : 0) | - (leaf1_edx & cpufeat_mask(X86_FEATURE_TSC) ? - X86_CR4_TSD : 0) | - (leaf1_edx & cpufeat_mask(X86_FEATURE_DE) ? - X86_CR4_DE : 0) | - (leaf1_edx & cpufeat_mask(X86_FEATURE_PSE) ? - X86_CR4_PSE : 0) | - (leaf1_edx & cpufeat_mask(X86_FEATURE_PAE) ? - X86_CR4_PAE : 0) | - (leaf1_edx & (cpufeat_mask(X86_FEATURE_MCE) | - cpufeat_mask(X86_FEATURE_MCA)) ? - X86_CR4_MCE : 0) | - (leaf1_edx & cpufeat_mask(X86_FEATURE_PGE) ? - X86_CR4_PGE : 0) | - X86_CR4_PCE | - (leaf1_edx & cpufeat_mask(X86_FEATURE_FXSR) ? - X86_CR4_OSFXSR : 0) | - (leaf1_edx & cpufeat_mask(X86_FEATURE_SSE) ? - X86_CR4_OSXMMEXCPT : 0) | - ((restore || nestedhvm_enabled(v->domain)) && - (leaf1_ecx & cpufeat_mask(X86_FEATURE_VMX)) ? - X86_CR4_VMXE : 0) | - (leaf7_0_ebx & cpufeat_mask(X86_FEATURE_FSGSBASE) ? - X86_CR4_FSGSBASE : 0) | - (leaf1_ecx & cpufeat_mask(X86_FEATURE_PCID) ? - X86_CR4_PCIDE : 0) | - (leaf1_ecx & cpufeat_mask(X86_FEATURE_XSAVE) ? - X86_CR4_OSXSAVE : 0) | - (leaf7_0_ebx & cpufeat_mask(X86_FEATURE_SMEP) ? - X86_CR4_SMEP : 0) | - (leaf7_0_ebx & cpufeat_mask(X86_FEATURE_SMAP) ? - X86_CR4_SMAP : 0) | - (leaf7_0_ecx & cpufeat_mask(X86_FEATURE_PKU) ? - X86_CR4_PKE : 0)); + p = &host_policy; + + /* Logic broken out simply to aid readability below. */ + mce = p->basic.mce || p->basic.mca; + vmxe = p->basic.vmx && (restore || nestedhvm_enabled(d)); + + return ((p->basic.vme ? X86_CR4_VME | X86_CR4_PVI : 0) | + (p->basic.tsc ? X86_CR4_TSD : 0) | + (p->basic.de ? X86_CR4_DE : 0) | + (p->basic.pse ? X86_CR4_PSE : 0) | + (p->basic.pae ? X86_CR4_PAE : 0) | + (mce ? X86_CR4_MCE : 0) | + (p->basic.pge ? X86_CR4_PGE : 0) | + X86_CR4_PCE | + (p->basic.fxsr ? X86_CR4_OSFXSR : 0) | + (p->basic.sse ? X86_CR4_OSXMMEXCPT : 0) | + (vmxe ? X86_CR4_VMXE : 0) | + (p->feat.fsgsbase ? X86_CR4_FSGSBASE : 0) | + (p->basic.pcid ? X86_CR4_PCIDE : 0) | + (p->basic.xsave ? X86_CR4_OSXSAVE : 0) | + (p->feat.smep ? X86_CR4_SMEP : 0) | + (p->feat.smap ? X86_CR4_SMAP : 0) | + (p->feat.pku ? X86_CR4_PKE : 0)); } static int hvm_load_cpu_ctxt(struct domain *d, hvm_domain_context_t *h) @@ -1054,7 +1026,7 @@ static int hvm_load_cpu_ctxt(struct domain *d, hvm_domain_context_t *h) return -EINVAL; } - if ( ctxt.cr4 & hvm_cr4_guest_reserved_bits(v, 1) ) + if ( ctxt.cr4 & ~hvm_cr4_guest_valid_bits(v, 1) ) { printk(XENLOG_G_ERR "HVM%d restore: bad CR4 %#" PRIx64 "\n", d->domain_id, ctxt.cr4); @@ -2390,7 +2362,7 @@ int hvm_set_cr4(unsigned long value, bool_t may_defer) struct vcpu *v = current; unsigned long old_cr; - if ( value & hvm_cr4_guest_reserved_bits(v, 0) ) + if ( value & ~hvm_cr4_guest_valid_bits(v, 0) ) { HVM_DBG_LOG(DBG_LEVEL_1, "Guest attempts to set reserved bit in CR4: %lx", diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h index 8c95c08..14b765e 100644 --- a/xen/include/asm-x86/hvm/hvm.h +++ b/xen/include/asm-x86/hvm/hvm.h @@ -615,7 +615,7 @@ static inline bool altp2m_vcpu_emulate_ve(struct vcpu *v) /* Check CR4/EFER values */ const char *hvm_efer_valid(const struct vcpu *v, uint64_t value, signed int cr0_pg); -unsigned long hvm_cr4_guest_reserved_bits(const struct vcpu *v, bool_t restore); +unsigned long hvm_cr4_guest_valid_bits(const struct vcpu *v, bool restore); /* * This must be defined as a macro instead of an inline function, -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel

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