Linux KVM/arm64 development list
 help / color / mirror / Atom feed
From: Gavin Shan <gshan@redhat.com>
To: kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, shan.gavin@gmail.com, pbonzini@redhat.com,
	will@kernel.org
Subject: [PATCH 1/6] arm64: Probe for the presence of KVM hypervisor services during boot
Date: Tue, 18 Aug 2020 11:13:14 +1000	[thread overview]
Message-ID: <20200818011319.91777-2-gshan@redhat.com> (raw)
In-Reply-To: <20200818011319.91777-1-gshan@redhat.com>

From: Will Deacon <will@kernel.org>

Although the SMCCC specification provides some limited functionality for
describing the presence of hypervisor and firmware services, this is
generally applicable only to functions designated as "Arm Architecture
Service Functions" and no portable discovery mechanism is provided for
standard hypervisor services, despite having a designated range of
function identifiers reserved by the specification.

In an attempt to avoid the need for additional firmware changes every
time a new function is added, introduce a UID to identify the service
provider as being compatible with KVM. Once this has been established,
additional services can be discovered via a feature bitmap.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 arch/arm64/include/asm/hypervisor.h | 11 ++++++++++
 arch/arm64/kernel/setup.c           | 32 +++++++++++++++++++++++++++++
 include/linux/arm-smccc.h           | 26 +++++++++++++++++++++++
 3 files changed, 69 insertions(+)

diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h
index f9cc1d021791..91e4bd890819 100644
--- a/arch/arm64/include/asm/hypervisor.h
+++ b/arch/arm64/include/asm/hypervisor.h
@@ -2,6 +2,17 @@
 #ifndef _ASM_ARM64_HYPERVISOR_H
 #define _ASM_ARM64_HYPERVISOR_H
 
+#include <linux/arm-smccc.h>
 #include <asm/xen/hypervisor.h>
 
+static inline bool kvm_arm_hyp_service_available(u32 func_id)
+{
+	extern DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS);
+
+	if (func_id >= ARM_SMCCC_KVM_NUM_FUNCS)
+		return -EINVAL;
+
+	return test_bit(func_id, __kvm_arm_hyp_services);
+}
+
 #endif
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 77c4c9bad1b8..6a0360793317 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/arm-smccc.h>
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/stddef.h>
@@ -275,6 +276,7 @@ static int __init reserve_memblock_reserved_regions(void)
 arch_initcall(reserve_memblock_reserved_regions);
 
 u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };
+DECLARE_BITMAP(__kvm_arm_hyp_services, ARM_SMCCC_KVM_NUM_FUNCS) = { };
 
 u64 cpu_logical_map(int cpu)
 {
@@ -282,6 +284,35 @@ u64 cpu_logical_map(int cpu)
 }
 EXPORT_SYMBOL_GPL(cpu_logical_map);
 
+static void __init kvm_init_hyp_services(void)
+{
+	struct arm_smccc_res res;
+	int i;
+
+	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);
+	}
+
+	pr_info("KVM hypervisor services detected (0x%08lx 0x%08lx 0x%08lx 0x%08lx)\n",
+		res.a3, res.a2, res.a1, res.a0);
+}
+
 void __init __no_sanitize_address setup_arch(char **cmdline_p)
 {
 	init_mm.start_code = (unsigned long) _text;
@@ -354,6 +385,7 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
 	else
 		psci_acpi_init();
 
+	kvm_init_hyp_services();
 	init_bootcpu_ops();
 	smp_init_cpus();
 	smp_build_mpidr_hash();
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 15c706fb0a37..1c699fc6dc12 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -49,11 +49,14 @@
 #define ARM_SMCCC_OWNER_OEM		3
 #define ARM_SMCCC_OWNER_STANDARD	4
 #define ARM_SMCCC_OWNER_STANDARD_HYP	5
+#define ARM_SMCCC_OWNER_VENDOR_HYP	6
 #define ARM_SMCCC_OWNER_TRUSTED_APP	48
 #define ARM_SMCCC_OWNER_TRUSTED_APP_END	49
 #define ARM_SMCCC_OWNER_TRUSTED_OS	50
 #define ARM_SMCCC_OWNER_TRUSTED_OS_END	63
 
+#define ARM_SMCCC_FUNC_QUERY_CALL_UID	0xff01
+
 #define ARM_SMCCC_QUIRK_NONE		0
 #define ARM_SMCCC_QUIRK_QCOM_A6		1 /* Save/restore register a6 */
 
@@ -99,6 +102,29 @@
 			   ARM_SMCCC_OWNER_STANDARD_HYP,	\
 			   0x21)
 
+#define ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID			\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_32,			\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,		\
+			   ARM_SMCCC_FUNC_QUERY_CALL_UID)
+
+/* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0	0xb66fb428U
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1	0xe911c52eU
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2	0x564bcaa9U
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3	0x743a004dU
+
+/* KVM "vendor specific" services */
+#define ARM_SMCCC_KVM_FUNC_FEATURES		0
+#define ARM_SMCCC_KVM_FUNC_FEATURES_2		127
+#define ARM_SMCCC_KVM_NUM_FUNCS			128
+
+#define ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID		\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,			\
+			   ARM_SMCCC_SMC_32,			\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,		\
+			   ARM_SMCCC_KVM_FUNC_FEATURES)
+
 /*
  * Return codes defined in ARM DEN 0070A
  * ARM DEN 0070A is now merged/consolidated into ARM DEN 0028 C
-- 
2.23.0

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

  reply	other threads:[~2020-08-18  1:13 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-18  1:13 [PATCH 0/6] Support Asynchronous Page Fault Gavin Shan
2020-08-18  1:13 ` Gavin Shan [this message]
2020-08-18  1:13 ` [PATCH 2/6] arm/arm64: KVM: Advertise KVM UID to guests via SMCCC Gavin Shan
2020-08-18  1:13 ` [PATCH 3/6] kvm/arm64: Export kvm_handle_user_mem_abort() with prefault mode Gavin Shan
2020-10-23 16:54   ` James Morse
2020-11-02  5:30     ` Gavin Shan
2020-08-18  1:13 ` [PATCH 4/6] arm64/kvm: Support async page fault Gavin Shan
2020-10-23 17:01   ` James Morse
2020-11-02  7:19     ` Gavin Shan
2020-08-18  1:13 ` [PATCH 5/6] drivers/acpi: Import ACPI APF table Gavin Shan
2020-10-23 16:55   ` James Morse
2020-08-18  1:13 ` [PATCH 6/6] arm64/kernel: Support async page fault Gavin Shan
2020-10-23 16:54 ` [PATCH 0/6] Support Asynchronous Page Fault James Morse
2020-10-31 14:18   ` Paolo Bonzini
2020-11-02  5:23   ` Gavin Shan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200818011319.91777-2-gshan@redhat.com \
    --to=gshan@redhat.com \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=maz@kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=shan.gavin@gmail.com \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox