| 45 | static struct xsave_limits vmm_xsave_limits; |
| 46 | |
| 47 | void |
| 48 | vmm_host_state_init(void) |
| 49 | { |
| 50 | int regs[4]; |
| 51 | |
| 52 | vmm_host_efer = rdmsr(MSR_EFER); |
| 53 | vmm_host_pat = rdmsr(MSR_PAT); |
| 54 | |
| 55 | /* |
| 56 | * We always want CR0.TS to be set when the processor does a VM exit. |
| 57 | * |
| 58 | * With emulation turned on unconditionally after a VM exit, we are |
| 59 | * able to trap inadvertent use of the FPU until the guest FPU state |
| 60 | * has been safely squirreled away. |
| 61 | */ |
| 62 | vmm_host_cr0 = rcr0() | CR0_TS; |
| 63 | |
| 64 | /* |
| 65 | * On non-PCID or PCID but without INVPCID support machines, |
| 66 | * we flush kernel i.e. global TLB entries, by temporary |
| 67 | * clearing the CR4.PGE bit, see invltlb_glob(). If |
| 68 | * preemption occurs at the wrong time, cached vmm_host_cr4 |
| 69 | * might store the value with CR4.PGE cleared. Since FreeBSD |
| 70 | * requires support for PG_G on amd64, just set it |
| 71 | * unconditionally. |
| 72 | */ |
| 73 | vmm_host_cr4 = rcr4() | CR4_PGE; |
| 74 | |
| 75 | /* |
| 76 | * Only permit a guest to use XSAVE if the host is using |
| 77 | * XSAVE. Only permit a guest to use XSAVE features supported |
| 78 | * by the host. This ensures that the FPU state used by the |
| 79 | * guest is always a subset of the saved guest FPU state. |
| 80 | * |
| 81 | * In addition, only permit known XSAVE features where the |
| 82 | * rules for which features depend on other features is known |
| 83 | * to properly emulate xsetbv. |
| 84 | */ |
| 85 | if (vmm_host_cr4 & CR4_XSAVE) { |
| 86 | vmm_xsave_limits.xsave_enabled = 1; |
| 87 | vmm_host_xcr0 = rxcr(0); |
| 88 | vmm_xsave_limits.xcr0_allowed = vmm_host_xcr0 & |
| 89 | (XFEATURE_AVX | XFEATURE_MPX | XFEATURE_AVX512); |
| 90 | |
| 91 | cpuid_count(0xd, 0x0, regs); |
| 92 | vmm_xsave_limits.xsave_max_size = regs[1]; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | uint64_t |
| 97 | vmm_get_host_pat(void) |