Merge tag 'kvm-riscv-6.13-2' of https://github.com/kvm-riscv/linux in…

…to HEAD

KVM/riscv changes for 6.13 part Rust-for-Linux#2

- Svade and Svadu extension support for Host and Guest/VM

Documentation/devicetree/bindings/riscv/extensions.yaml

@@ -171,6 +171,34 @@ properties:
             ratified at commit 3f9ed34 ("Add ability to manually trigger
             workflow. (#2)") of riscv-time-compare.
 
+        - const: svade
+          description: |
+            The standard Svade supervisor-level extension for SW-managed PTE A/D
+            bit updates as ratified in the 20240213 version of the privileged
+            ISA specification.
+
+            Both Svade and Svadu extensions control the hardware behavior when
+            the PTE A/D bits need to be set. The default behavior for the four
+            possible combinations of these extensions in the device tree are:
+            1) Neither Svade nor Svadu present in DT => It is technically
+               unknown whether the platform uses Svade or Svadu. Supervisor
+               software should be prepared to handle either hardware updating
+               of the PTE A/D bits or page faults when they need updated.
+            2) Only Svade present in DT => Supervisor must assume Svade to be
+               always enabled.
+            3) Only Svadu present in DT => Supervisor must assume Svadu to be
+               always enabled.
+            4) Both Svade and Svadu present in DT => Supervisor must assume
+               Svadu turned-off at boot time. To use Svadu, supervisor must
+               explicitly enable it using the SBI FWFT extension.
+
+        - const: svadu
+          description: |
+            The standard Svadu supervisor-level extension for hardware updating
+            of PTE A/D bits as ratified in the 20240528 version of the
+            privileged ISA specification. Please refer to Svade dt-binding
+            description for more details.
+
         - const: svinval
           description:
             The standard Svinval supervisor-level extension for fine-grained

arch/riscv/Kconfig

@@ -32,6 +32,7 @@ config RISCV
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
+	select ARCH_HAS_HW_PTE_YOUNG
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_KERNEL_FPU_SUPPORT if 64BIT && FPU
 	select ARCH_HAS_MEMBARRIER_CALLBACKS

arch/riscv/include/asm/csr.h

@@ -199,6 +199,7 @@
 /* xENVCFG flags */
 #define ENVCFG_STCE			(_AC(1, ULL) << 63)
 #define ENVCFG_PBMTE			(_AC(1, ULL) << 62)
+#define ENVCFG_ADUE			(_AC(1, ULL) << 61)
 #define ENVCFG_PMM			(_AC(0x3, ULL) << 32)
 #define ENVCFG_PMM_PMLEN_0		(_AC(0x0, ULL) << 32)
 #define ENVCFG_PMM_PMLEN_7		(_AC(0x2, ULL) << 32)

arch/riscv/include/asm/hwcap.h

@@ -98,6 +98,8 @@
 #define RISCV_ISA_EXT_SSNPM		89
 #define RISCV_ISA_EXT_ZABHA		90
 #define RISCV_ISA_EXT_ZICCRSE		91
+#define RISCV_ISA_EXT_SVADE		92
+#define RISCV_ISA_EXT_SVADU		93
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 

arch/riscv/include/asm/pgtable.h

@@ -113,6 +113,7 @@
 #include <asm/tlbflush.h>
 #include <linux/mm_types.h>
 #include <asm/compat.h>
+#include <asm/cpufeature.h>
 
 #define __page_val_to_pfn(_val)  (((_val) & _PAGE_PFN_MASK) >> _PAGE_PFN_SHIFT)
 
@@ -284,7 +285,6 @@ static inline pte_t pud_pte(pud_t pud)
 }
 
 #ifdef CONFIG_RISCV_ISA_SVNAPOT
-#include <asm/cpufeature.h>
 
 static __always_inline bool has_svnapot(void)
 {
@@ -655,6 +655,17 @@ static inline pgprot_t pgprot_writecombine(pgprot_t _prot)
 	return __pgprot(prot);
 }
 
+/*
+ * Both Svade and Svadu control the hardware behavior when the PTE A/D bits need to be set. By
+ * default the M-mode firmware enables the hardware updating scheme when only Svadu is present in
+ * DT.
+ */
+#define arch_has_hw_pte_young arch_has_hw_pte_young
+static inline bool arch_has_hw_pte_young(void)
+{
+	return riscv_has_extension_unlikely(RISCV_ISA_EXT_SVADU);
+}
+
 /*
  * THP functions
  */

arch/riscv/include/uapi/asm/kvm.h

@@ -177,6 +177,8 @@ enum KVM_RISCV_ISA_EXT_ID {
 	KVM_RISCV_ISA_EXT_ZAWRS,
 	KVM_RISCV_ISA_EXT_SMNPM,
 	KVM_RISCV_ISA_EXT_SSNPM,
+	KVM_RISCV_ISA_EXT_SVADE,
+	KVM_RISCV_ISA_EXT_SVADU,
 	KVM_RISCV_ISA_EXT_MAX,
 };
 

arch/riscv/kernel/cpufeature.c

@@ -135,6 +135,16 @@ static int riscv_ext_zcf_validate(const struct riscv_isa_ext_data *data,
 	return -EPROBE_DEFER;
 }
 
+static int riscv_ext_svadu_validate(const struct riscv_isa_ext_data *data,
+				    const unsigned long *isa_bitmap)
+{
+	/* SVADE has already been detected, use SVADE only */
+	if (__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_SVADE))
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
 static const unsigned int riscv_zk_bundled_exts[] = {
 	RISCV_ISA_EXT_ZBKB,
 	RISCV_ISA_EXT_ZBKC,
@@ -386,6 +396,8 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
 	__RISCV_ISA_EXT_SUPERSET(ssnpm, RISCV_ISA_EXT_SSNPM, riscv_xlinuxenvcfg_exts),
 	__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
+	__RISCV_ISA_EXT_DATA(svade, RISCV_ISA_EXT_SVADE),
+	__RISCV_ISA_EXT_DATA_VALIDATE(svadu, RISCV_ISA_EXT_SVADU, riscv_ext_svadu_validate),
 	__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
 	__RISCV_ISA_EXT_DATA(svnapot, RISCV_ISA_EXT_SVNAPOT),
 	__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),

arch/riscv/kvm/vcpu.c

@@ -551,6 +551,10 @@ static void kvm_riscv_vcpu_setup_config(struct kvm_vcpu *vcpu)
 	if (riscv_isa_extension_available(isa, ZICBOZ))
 		cfg->henvcfg |= ENVCFG_CBZE;
 
+	if (riscv_isa_extension_available(isa, SVADU) &&
+	    !riscv_isa_extension_available(isa, SVADE))
+		cfg->henvcfg |= ENVCFG_ADUE;
+
 	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN)) {
 		cfg->hstateen0 |= SMSTATEEN0_HSENVCFG;
 		if (riscv_isa_extension_available(isa, SSAIA))

arch/riscv/kvm/vcpu_onereg.c

@@ -15,6 +15,7 @@
 #include <asm/cacheflush.h>
 #include <asm/cpufeature.h>
 #include <asm/kvm_vcpu_vector.h>
+#include <asm/pgtable.h>
 #include <asm/vector.h>
 
 #define KVM_RISCV_BASE_ISA_MASK		GENMASK(25, 0)
@@ -40,6 +41,8 @@ static const unsigned long kvm_isa_ext_arr[] = {
 	KVM_ISA_EXT_ARR(SSCOFPMF),
 	KVM_ISA_EXT_ARR(SSNPM),
 	KVM_ISA_EXT_ARR(SSTC),
+	KVM_ISA_EXT_ARR(SVADE),
+	KVM_ISA_EXT_ARR(SVADU),
 	KVM_ISA_EXT_ARR(SVINVAL),
 	KVM_ISA_EXT_ARR(SVNAPOT),
 	KVM_ISA_EXT_ARR(SVPBMT),
@@ -112,6 +115,12 @@ static bool kvm_riscv_vcpu_isa_enable_allowed(unsigned long ext)
 	case KVM_RISCV_ISA_EXT_SSCOFPMF:
 		/* Sscofpmf depends on interrupt filtering defined in ssaia */
 		return __riscv_isa_extension_available(NULL, RISCV_ISA_EXT_SSAIA);
+	case KVM_RISCV_ISA_EXT_SVADU:
+		/*
+		 * The henvcfg.ADUE is read-only zero if menvcfg.ADUE is zero.
+		 * Guest OS can use Svadu only when host OS enable Svadu.
+		 */
+		return arch_has_hw_pte_young();
 	case KVM_RISCV_ISA_EXT_V:
 		return riscv_v_vstate_ctrl_user_allowed();
 	default:
@@ -185,6 +194,12 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext)
 	/* Extensions which can be disabled using Smstateen */
 	case KVM_RISCV_ISA_EXT_SSAIA:
 		return riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN);
+	case KVM_RISCV_ISA_EXT_SVADE:
+		/*
+		 * The henvcfg.ADUE is read-only zero if menvcfg.ADUE is zero.
+		 * Svade is not allowed to disable when the platform use Svade.
+		 */
+		return arch_has_hw_pte_young();
 	default:
 		break;
 	}

tools/testing/selftests/kvm/riscv/get-reg-list.c

@@ -47,6 +47,8 @@ bool filter_reg(__u64 reg)
 	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SSCOFPMF:
 	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SSNPM:
 	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SSTC:
+	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SVADE:
+	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SVADU:
 	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SVINVAL:
 	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SVNAPOT:
 	case KVM_REG_RISCV_ISA_EXT | KVM_REG_RISCV_ISA_SINGLE | KVM_RISCV_ISA_EXT_SVPBMT:
@@ -422,6 +424,8 @@ static const char *isa_ext_single_id_to_str(__u64 reg_off)
 		KVM_ISA_EXT_ARR(SSCOFPMF),
 		KVM_ISA_EXT_ARR(SSNPM),
 		KVM_ISA_EXT_ARR(SSTC),
+		KVM_ISA_EXT_ARR(SVADE),
+		KVM_ISA_EXT_ARR(SVADU),
 		KVM_ISA_EXT_ARR(SVINVAL),
 		KVM_ISA_EXT_ARR(SVNAPOT),
 		KVM_ISA_EXT_ARR(SVPBMT),
@@ -955,6 +959,8 @@ KVM_ISA_EXT_SUBLIST_CONFIG(smstateen, SMSTATEEN);
 KVM_ISA_EXT_SIMPLE_CONFIG(sscofpmf, SSCOFPMF);
 KVM_ISA_EXT_SIMPLE_CONFIG(ssnpm, SSNPM);
 KVM_ISA_EXT_SIMPLE_CONFIG(sstc, SSTC);
+KVM_ISA_EXT_SIMPLE_CONFIG(svade, SVADE);
+KVM_ISA_EXT_SIMPLE_CONFIG(svadu, SVADU);
 KVM_ISA_EXT_SIMPLE_CONFIG(svinval, SVINVAL);
 KVM_ISA_EXT_SIMPLE_CONFIG(svnapot, SVNAPOT);
 KVM_ISA_EXT_SIMPLE_CONFIG(svpbmt, SVPBMT);
@@ -1020,6 +1026,8 @@ struct vcpu_reg_list *vcpu_configs[] = {
 	&config_sscofpmf,
 	&config_ssnpm,
 	&config_sstc,
+	&config_svade,
+	&config_svadu,
 	&config_svinval,
 	&config_svnapot,
 	&config_svpbmt,