arm64: KVM: Use SMCCC_ARCH_WORKAROUND_1 for Falkor BP hardening

The function SMCCC_ARCH_WORKAROUND_1 was introduced as part of SMC
V1.1 Calling Convention to mitigate CVE-2017-5715. This patch uses
the standard call SMCCC_ARCH_WORKAROUND_1 for Falkor chips instead
of Silicon provider service ID 0xC2001700.

Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index d4cc54ed0656175b03ad9a190daa146477c5588c..c7dfe68fbcc77e99a5be64dde1c1fa69817b21ff 100644 (file)
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -43,7 +43,7 @@
 #define ARM64_SVE                              22
 #define ARM64_UNMAP_KERNEL_AT_EL0              23
 #define ARM64_HARDEN_BRANCH_PREDICTOR          24
-#define ARM64_HARDEN_BP_POST_GUEST_EXIT                25
+/* #define ARM64_UNUSED_CAP_TO_BE_REMOVED      25 */
 #define ARM64_HAS_RAS_EXTN                     26
 
 #define ARM64_NCAPS                            27

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index d53d40704416699c81fe923c5af15ce8a79993a9..f6648a3e4152c3cd95652563d3003abc090795df 100644 (file)
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -71,8 +71,6 @@ extern u32 __kvm_get_mdcr_el2(void);
 
 extern u32 __init_stage2_translation(void);
 
-extern void __qcom_hyp_sanitize_btac_predictors(void);
-
 #else /* __ASSEMBLY__ */
 
 .macro get_host_ctxt reg, tmp

diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S
index bb0b67722e86230ffc798fb7d52559328e43eb07..9404f6aecda7a3f396e377e88cc42960b15c3e88 100644 (file)
--- a/arch/arm64/kernel/bpi.S
+++ b/arch/arm64/kernel/bpi.S
@@ -74,14 +74,6 @@ ENTRY(__bp_harden_hyp_vecs_end)
 
        .popsection
 
-ENTRY(__qcom_hyp_sanitize_link_stack_start)
-       stp     x29, x30, [sp, #-16]!
-       .rept   16
-       bl      . + 4
-       .endr
-       ldp     x29, x30, [sp], #16
-ENTRY(__qcom_hyp_sanitize_link_stack_end)
-
 .macro smccc_workaround_1 inst
        sub     sp, sp, #(8 * 4)
        stp     x2, x3, [sp, #(8 * 0)]

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index aacdc118c4c9d456194aec76f01272ff1a08bf75..caa73af7d26e11ebb5ecbdd92e689d1549bf585a 100644 (file)
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -69,8 +69,6 @@ atomic_t arm64_el2_vector_last_slot = ATOMIC_INIT(-1);
 DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
 
 #ifdef CONFIG_KVM
-extern char __qcom_hyp_sanitize_link_stack_start[];
-extern char __qcom_hyp_sanitize_link_stack_end[];
 extern char __smccc_workaround_1_smc_start[];
 extern char __smccc_workaround_1_smc_end[];
 extern char __smccc_workaround_1_hvc_start[];
@@ -114,8 +112,6 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
        spin_unlock(&bp_lock);
 }
 #else
-#define __qcom_hyp_sanitize_link_stack_start   NULL
-#define __qcom_hyp_sanitize_link_stack_end     NULL
 #define __smccc_workaround_1_smc_start         NULL
 #define __smccc_workaround_1_smc_end           NULL
 #define __smccc_workaround_1_hvc_start         NULL
@@ -160,12 +156,25 @@ static void call_hvc_arch_workaround_1(void)
        arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_WORKAROUND_1, NULL);
 }
 
+static void qcom_link_stack_sanitization(void)
+{
+       u64 tmp;
+
+       asm volatile("mov       %0, x30         \n"
+                    ".rept     16              \n"
+                    "bl        . + 4           \n"
+                    ".endr                     \n"
+                    "mov       x30, %0         \n"
+                    : "=&r" (tmp));
+}
+
 static int enable_smccc_arch_workaround_1(void *data)
 {
        const struct arm64_cpu_capabilities *entry = data;
        bp_hardening_cb_t cb;
        void *smccc_start, *smccc_end;
        struct arm_smccc_res res;
+       u32 midr = read_cpuid_id();
 
        if (!entry->matches(entry, SCOPE_LOCAL_CPU))
                return 0;
@@ -198,33 +207,15 @@ static int enable_smccc_arch_workaround_1(void *data)
                return 0;
        }
 
+       if (((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR) ||
+           ((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR_V1))
+               cb = qcom_link_stack_sanitization;
+
        install_bp_hardening_cb(entry, cb, smccc_start, smccc_end);
 
        return 0;
 }
 
-static void qcom_link_stack_sanitization(void)
-{
-       u64 tmp;
-
-       asm volatile("mov       %0, x30         \n"
-                    ".rept     16              \n"
-                    "bl        . + 4           \n"
-                    ".endr                     \n"
-                    "mov       x30, %0         \n"
-                    : "=&r" (tmp));
-}
-
-static int qcom_enable_link_stack_sanitization(void *data)
-{
-       const struct arm64_cpu_capabilities *entry = data;
-
-       install_bp_hardening_cb(entry, qcom_link_stack_sanitization,
-                               __qcom_hyp_sanitize_link_stack_start,
-                               __qcom_hyp_sanitize_link_stack_end);
-
-       return 0;
-}
 #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
 
 #define MIDR_RANGE(model, min, max) \
@@ -399,20 +390,12 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
        {
                .capability = ARM64_HARDEN_BRANCH_PREDICTOR,
                MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1),
-               .enable = qcom_enable_link_stack_sanitization,
-       },
-       {
-               .capability = ARM64_HARDEN_BP_POST_GUEST_EXIT,
-               MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1),
+               .enable = enable_smccc_arch_workaround_1,
        },
        {
                .capability = ARM64_HARDEN_BRANCH_PREDICTOR,
                MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR),
-               .enable = qcom_enable_link_stack_sanitization,
-       },
-       {
-               .capability = ARM64_HARDEN_BP_POST_GUEST_EXIT,
-               MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR),
+               .enable = enable_smccc_arch_workaround_1,
        },
        {
                .capability = ARM64_HARDEN_BRANCH_PREDICTOR,

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 1f458f7c3b44066966750da2b54f9134f43bd9fb..e41a161d313a6f93ab92690bce5053b7f2b952c8 100644 (file)
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -209,15 +209,3 @@ alternative_endif
 
        eret
 ENDPROC(__fpsimd_guest_restore)
-
-ENTRY(__qcom_hyp_sanitize_btac_predictors)
-       /**
-        * Call SMC64 with Silicon provider serviceID 23<<8 (0xc2001700)
-        * 0xC2000000-0xC200FFFF: assigned to SiP Service Calls
-        * b15-b0: contains SiP functionID
-        */
-       movz    x0, #0x1700
-       movk    x0, #0xc200, lsl #16
-       smc     #0
-       ret
-ENDPROC(__qcom_hyp_sanitize_btac_predictors)

diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 07b57217326538d176f7942dcf708a5ade831623..d9645236e474972ee92c5482bcd0348773ceaf07 100644 (file)
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -472,16 +472,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
                /* And we're baaack! */
        } while (fixup_guest_exit(vcpu, &exit_code));
 
-       if (cpus_have_const_cap(ARM64_HARDEN_BP_POST_GUEST_EXIT)) {
-               u32 midr = read_cpuid_id();
-
-               /* Apply BTAC predictors mitigation to all Falkor chips */
-               if (((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR) ||
-                   ((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR_V1)) {
-                       __qcom_hyp_sanitize_btac_predictors();
-               }
-       }
-
        fp_enabled = __fpsimd_enabled_nvhe();
 
        __sysreg_save_state_nvhe(guest_ctxt);