This patch only saves and restores FP/SIMD registers on Guest access. To do this cptr_el2 FP/SIMD trap is set on Guest entry and later checked on exit. The non-VHE path has been tested, future work would add VHE support. Signed-off-by: Mario Smarduch <m.smarduch@xxxxxxxxxxx> --- arch/arm64/include/asm/kvm_arm.h | 5 +++- arch/arm64/kvm/hyp.S | 58 +++++++++++++++++++++++++++++++++++++--- 2 files changed, 58 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index c8998c0..0a1d152 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -172,10 +172,13 @@ #define HSTR_EL2_TTEE (1 << 16) #define HSTR_EL2_T(x) (1 << x) +/* Hyp Coproccessor Trap Register Shifts */ +#define CPTR_EL2_TFP_SHIFT 10 + /* Hyp Coprocessor Trap Register */ #define CPTR_EL2_TCPAC (1 << 31) #define CPTR_EL2_TTA (1 << 20) -#define CPTR_EL2_TFP (1 << 10) +#define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT) /* Hyp Debug Configuration Register bits */ #define MDCR_EL2_TDRA (1 << 11) diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 64a5280..9d154ed 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -731,6 +731,15 @@ ifnvhe "mrs \tmp, hcr_el2", _S_(ldr \tmp, [x0, #VCPU_HCR_EL2]) tbz \tmp, #KVM_ARM64_DEBUG_DIRTY_SHIFT, \target .endm +/* + * For non-VHE - branch to target if CPTR_EL2.TFP bit is set (VFP/SIMD trapping + * enabled). For VHE do nothing. + */ +.macro skip_fpsimd_state tmp, target +ifnvhe "mrs \tmp, cptr_el2", nop +ifnvhe _S_(tbnz \tmp, #CPTR_EL2_TFP_SHIFT, \target), nop +.endm + .macro compute_debug_state target // Compute debug state: If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY // is set, we do a full save/restore cycle and disable trapping. @@ -823,7 +832,7 @@ ifnvhe "mrs \tmp, hcr_el2", _S_(ldr \tmp, [x0, #VCPU_HCR_EL2]) adr x3, __kvm_hyp_vector ifnvhe nop, "msr vbar_el1, x3" ifnvhe nop, "mrs x2, cpacr_el1" -ifnvhe _S_(ldr x2, =(CPTR_EL2_TTA)), "orr x2, x2, #(1 << 28)" +ifnvhe _S_(ldr x2, =(CPTR_EL2_TTA|CPTR_EL2_TFP)), "orr x2, x2, #(1 << 28)" ifnvhe "msr cptr_el2, x2", "msr cpacr_el1, x2" mov x2, #(1 << 15) // Trap CP15 Cr=15 @@ -851,7 +860,7 @@ ifnvhe nop, _S_(orr x2, x2, #HCR_E2H) ifnvhe nop, "mrs x2, cpacr_el1" ifnvhe nop, "movn x3, #(1 << 12), lsl #16" ifnvhe nop, "and x2, x2, x3" -ifnvhe "msr cptr_el2, xzr", "msr cpacr_el1, x2" +ifnvhe nop, "msr cpacr_el1, x2" msr hstr_el2, xzr mrs x2, mdcr_el2 @@ -988,6 +997,33 @@ __restore_fpsimd: ret /* + * For non-VHE - on first FP/SIMD access, restore guest, save host registers + * and disable future trapping. For VHE this should never get called. + */ +switch_to_guest_fpsimd: + push x4, lr + + mrs x2, cptr_el2 + bic x2, x2, #CPTR_EL2_TFP + msr cptr_el2, x2 + + mrs x0, tpidr_el2 + + ldr x2, [x0, #VCPU_HOST_CONTEXT] + kern_hyp_va x2 + bl __save_fpsimd + + add x2, x0, #VCPU_CONTEXT + bl __restore_fpsimd + + pop x4, lr + pop x2, x3 + pop x0, x1 + + eret + + +/* * u64 __kvm_vcpu_run(struct kvm_vcpu *vcpu); * * This is the world switch. The first half of the function @@ -1007,7 +1043,7 @@ ENTRY(__kvm_vcpu_run) kern_hyp_va x2 save_host_regs - bl __save_fpsimd +ifnvhe nop, "bl __save_fpsimd" ifnvhe "bl __save_sysregs", "nop" bl __save_shared_sysregs @@ -1025,7 +1061,7 @@ ifnvhe "bl __save_sysregs", "nop" bl __restore_sysregs bl __restore_shared_sysregs - bl __restore_fpsimd +ifnvhe "nop", "bl __restore_fpsimd" skip_debug_state x3, 1f bl __restore_debug @@ -1044,7 +1080,9 @@ __kvm_vcpu_return: add x2, x0, #VCPU_CONTEXT save_guest_regs + skip_fpsimd_state x3, 1f bl __save_fpsimd +1: bl __save_sysregs bl __save_shared_sysregs @@ -1072,7 +1110,11 @@ __kvm_vcpu_return_irq: ifnvhe "bl __restore_sysregs", "nop" bl __restore_shared_sysregs + skip_fpsimd_state x3, 1f bl __restore_fpsimd +1: + /* For non-VHE - Clear FPSIMD and Trace trapping, do nothig for VHE */ +ifnvhe "msr cptr_el2, xzr", "nop" skip_debug_state x3, 1f // Clear the dirty flag for the next run, as all the state has @@ -1298,6 +1340,14 @@ el1_trap: * x1: ESR * x2: ESR_EC */ + + /* + * For non-VHE Guest accessed FP/SIMD registers, save host, restore + * guest. For VHE condition should never be true. + */ + cmp x2, #ESR_ELx_EC_FP_ASIMD + b.eq switch_to_guest_fpsimd + cmp x2, #ESR_ELx_EC_DABT_LOW mov x0, #ESR_ELx_EC_IABT_LOW ccmp x2, x0, #4, ne -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
