Messages in this thread Patch in this message | | | Date | Fri, 05 Feb 2021 16:50:27 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v17 1/7] arm/arm64: Probe for the presence of KVM hypervisor |
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On 2021-02-05 11:19, Will Deacon wrote: > On Fri, Feb 05, 2021 at 09:11:00AM +0000, Steven Price wrote: >> On 02/02/2021 14:11, Marc Zyngier wrote: >> > diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c >> > new file mode 100644 >> > index 000000000000..23ce1ded88b4 >> > --- /dev/null >> > +++ b/drivers/firmware/smccc/kvm_guest.c >> > @@ -0,0 +1,51 @@ >> > +// SPDX-License-Identifier: GPL-2.0 >> > + >> > +#define pr_fmt(fmt) "smccc: KVM: " fmt >> > + >> > +#include <linux/init.h> >> > +#include <linux/arm-smccc.h> >> > +#include <linux/kernel.h> >> > +#include <linux/string.h> >> > + >> > +static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_after_init = { }; >> > + >> > +void __init kvm_init_hyp_services(void) >> > +{ >> > + int i; >> > + struct arm_smccc_res res; >> > + >> > + if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) >> > + return; >> > + >> > + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res); >> > + if (res.a0 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 || >> > + res.a1 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 || >> > + res.a2 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 || >> > + res.a3 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3) >> > + return; >> > + >> > + memset(&res, 0, sizeof(res)); >> > + arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, &res); >> > + for (i = 0; i < 32; ++i) { >> > + if (res.a0 & (i)) >> > + set_bit(i + (32 * 0), __kvm_arm_hyp_services); >> > + if (res.a1 & (i)) >> > + set_bit(i + (32 * 1), __kvm_arm_hyp_services); >> > + if (res.a2 & (i)) >> > + set_bit(i + (32 * 2), __kvm_arm_hyp_services); >> > + if (res.a3 & (i)) >> > + set_bit(i + (32 * 3), __kvm_arm_hyp_services); >> >> The bit shifts are missing, the tests should be of the form: >> >> if (res.a0 & (1 << i)) >> >> Or indeed using a BIT() macro. > > Maybe even test_bit()?
Actually, maybe not doing things a-bit-at-a-time is less error prone. See below what I intend to fold in.
Thanks,
M.
diff --git a/drivers/firmware/smccc/kvm_guest.c b/drivers/firmware/smccc/kvm_guest.c index 00bf3c7969fc..08836f2f39ee 100644 --- a/drivers/firmware/smccc/kvm_guest.c +++ b/drivers/firmware/smccc/kvm_guest.c @@ -2,8 +2,8 @@
#define pr_fmt(fmt) "smccc: KVM: " fmt
-#include <linux/init.h> #include <linux/arm-smccc.h> +#include <linux/bitmap.h> #include <linux/kernel.h> #include <linux/string.h>
@@ -13,8 +13,8 @@ static DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) __ro_afte
void __init kvm_init_hyp_services(void) { - int i; struct arm_smccc_res res; + u32 val[4];
if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC) return; @@ -28,16 +28,13 @@ void __init kvm_init_hyp_services(void)
memset(&res, 0, sizeof(res)); arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID, &res); - for (i = 0; i < 32; ++i) { - if (res.a0 & (i)) - set_bit(i + (32 * 0), __kvm_arm_hyp_services); - if (res.a1 & (i)) - set_bit(i + (32 * 1), __kvm_arm_hyp_services); - if (res.a2 & (i)) - set_bit(i + (32 * 2), __kvm_arm_hyp_services); - if (res.a3 & (i)) - set_bit(i + (32 * 3), __kvm_arm_hyp_services); - } + + val[0] = lower_32_bits(res.a0); + val[1] = lower_32_bits(res.a1); + val[2] = lower_32_bits(res.a2); + val[3] = lower_32_bits(res.a3); + + bitmap_from_arr32(__kvm_arm_hyp_services, val, ARM_SMCCC_KVM_NUM_FUNCS);
pr_info("hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n", res.a3, res.a2, res.a1, res.a0);
-- Jazz is not dead. It just smells funny...
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