Merge tag 'loongarch-kvm-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD

LoongArch KVM changes for v6.10

1. Add ParaVirt IPI support.
2. Add software breakpoint support.
3. Add mmio trace events support.

4 files changed, 43 insertions, 8 deletions

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 12ade343a17e..be40474de6e4 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -535,7 +535,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	perf_capabilities = vcpu_get_perf_capabilities(vcpu);
 	if (cpuid_model_is_consistent(vcpu) &&
 	    (perf_capabilities & PMU_CAP_LBR_FMT))
-		x86_perf_get_lbr(&lbr_desc->records);
+		memcpy(&lbr_desc->records, &vmx_lbr_caps, sizeof(vmx_lbr_caps));
 	else
 		lbr_desc->records.nr = 0;
 
diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
index 2bfbf758d061..f6986dee6f8c 100644
--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -275,6 +275,8 @@ SYM_INNER_LABEL_ALIGN(vmx_vmexit, SYM_L_GLOBAL)
 
 	call vmx_spec_ctrl_restore_host
 
+	CLEAR_BRANCH_HISTORY_VMEXIT
+
 	/* Put return value in AX */
 	mov %_ASM_BX, %_ASM_AX
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f4644f61d770..ad36e5eb6667 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -219,6 +219,8 @@ module_param(ple_window_max, uint, 0444);
 int __read_mostly pt_mode = PT_MODE_SYSTEM;
 module_param(pt_mode, int, S_IRUGO);
 
+struct x86_pmu_lbr __ro_after_init vmx_lbr_caps;
+
 static DEFINE_STATIC_KEY_FALSE(vmx_l1d_should_flush);
 static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_cond);
 static DEFINE_MUTEX(vmx_l1d_flush_mutex);
@@ -7905,10 +7907,9 @@ void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	vmx_update_exception_bitmap(vcpu);
 }
 
-static u64 vmx_get_perf_capabilities(void)
+static __init u64 vmx_get_perf_capabilities(void)
 {
 	u64 perf_cap = PMU_CAP_FW_WRITES;
-	struct x86_pmu_lbr lbr;
 	u64 host_perf_cap = 0;
 
 	if (!enable_pmu)
@@ -7918,15 +7919,43 @@ static u64 vmx_get_perf_capabilities(void)
 		rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
 
 	if (!cpu_feature_enabled(X86_FEATURE_ARCH_LBR)) {
-		x86_perf_get_lbr(&lbr);
-		if (lbr.nr)
+		x86_perf_get_lbr(&vmx_lbr_caps);
+
+		/*
+		 * KVM requires LBR callstack support, as the overhead due to
+		 * context switching LBRs without said support is too high.
+		 * See intel_pmu_create_guest_lbr_event() for more info.
+		 */
+		if (!vmx_lbr_caps.has_callstack)
+			memset(&vmx_lbr_caps, 0, sizeof(vmx_lbr_caps));
+		else if (vmx_lbr_caps.nr)
 			perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
 	}
 
 	if (vmx_pebs_supported()) {
 		perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
-		if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
-			perf_cap &= ~PERF_CAP_PEBS_BASELINE;
+
+		/*
+		 * Disallow adaptive PEBS as it is functionally broken, can be
+		 * used by the guest to read *host* LBRs, and can be used to
+		 * bypass userspace event filters.  To correctly and safely
+		 * support adaptive PEBS, KVM needs to:
+		 *
+		 * 1. Account for the ADAPTIVE flag when (re)programming fixed
+		 *    counters.
+		 *
+		 * 2. Gain support from perf (or take direct control of counter
+		 *    programming) to support events without adaptive PEBS
+		 *    enabled for the hardware counter.
+		 *
+		 * 3. Ensure LBR MSRs cannot hold host data on VM-Entry with
+		 *    adaptive PEBS enabled and MSR_PEBS_DATA_CFG.LBRS=1.
+		 *
+		 * 4. Document which PMU events are effectively exposed to the
+		 *    guest via adaptive PEBS, and make adaptive PEBS mutually
+		 *    exclusive with KVM_SET_PMU_EVENT_FILTER if necessary.
+		 */
+		perf_cap &= ~PERF_CAP_PEBS_BASELINE;
 	}
 
 	return perf_cap;
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 0da79a386825..e4a605c5808e 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -15,6 +15,7 @@
 #include "vmx_ops.h"
 #include "../cpuid.h"
 #include "run_flags.h"
+#include "../mmu.h"
 
 #define MSR_TYPE_R	1
 #define MSR_TYPE_W	2
@@ -109,6 +110,8 @@ struct lbr_desc {
 	bool msr_passthrough;
 };
 
+extern struct x86_pmu_lbr vmx_lbr_caps;
+
 /*
  * The nested_vmx structure is part of vcpu_vmx, and holds information we need
  * for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -723,7 +726,8 @@ static inline bool vmx_need_pf_intercept(struct kvm_vcpu *vcpu)
 	if (!enable_ept)
 		return true;
 
-	return allow_smaller_maxphyaddr && cpuid_maxphyaddr(vcpu) < boot_cpu_data.x86_phys_bits;
+	return allow_smaller_maxphyaddr &&
+	       cpuid_maxphyaddr(vcpu) < kvm_get_shadow_phys_bits();
 }
 
 static inline bool is_unrestricted_guest(struct kvm_vcpu *vcpu)