[PATCH OLK-6.6 v3 08/19] KVM: arm64: Exclude FP ownership from kvm_vcpu_arch

25 Sep 2024

From: Marc Zyngier maz@kernel.org
mainline inclusion
from mainline-v6.9-rc1
commit 5294afdbf45aced5295fe5941c58b40c41c23800
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8EC9K
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
In retrospect, it is fairly obvious that the FP state ownership
is only meaningful for a given CPU, and that locating this
information in the vcpu was just a mistake.
Move the ownership tracking into the host data structure, and
rename it from fp_state to fp_owner, which is a better description
(name suggested by Mark Brown).
Reviewed-by: Mark Brown broonie@kernel.org
Signed-off-by: Marc Zyngier maz@kernel.org
Signed-off-by: Junhao He hejunhao3@huawei.com
---
 arch/arm64/include/asm/kvm_emulate.h    |  4 ++--
 arch/arm64/include/asm/kvm_host.h       | 14 +++++++-------
 arch/arm64/kvm/arm.c                    |  6 ------
 arch/arm64/kvm/fpsimd.c                 | 10 +++++-----
 arch/arm64/kvm/hyp/include/hyp/switch.h |  6 +++---
 arch/arm64/kvm/hyp/nvhe/hyp-main.c      |  2 --
 arch/arm64/kvm/hyp/nvhe/switch.c        |  2 +-
 arch/arm64/kvm/hyp/vhe/switch.c         |  2 +-
 8 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 2293caab9f8f..cbe5187f1f12 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -616,7 +616,7 @@ static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu)
    	val = (CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN);
if (!vcpu_has_sve(vcpu) ||
-		    (vcpu->arch.fp_state != FP_STATE_GUEST_OWNED))
+		    (*host_data_ptr(fp_owner) != FP_STATE_GUEST_OWNED))
    		val |= CPACR_EL1_ZEN_EL1EN | CPACR_EL1_ZEN_EL0EN;
    	if (cpus_have_final_cap(ARM64_SME))
    		val |= CPACR_EL1_SMEN_EL1EN | CPACR_EL1_SMEN_EL0EN;
@@ -624,7 +624,7 @@ static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu)
    	val = CPTR_NVHE_EL2_RES1;
if (vcpu_has_sve(vcpu) &&
-		    (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED))
+		    (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED))
    		val |= CPTR_EL2_TZ;
    	if (cpus_have_final_cap(ARM64_SME))
    		val &= ~CPTR_EL2_TSM;
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27cfeaa097d9..d475cc04260e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -465,6 +465,13 @@ struct kvm_host_data {
    struct kvm_cpu_context host_ctxt;
    struct user_fpsimd_state *fpsimd_state;	/* hyp VA */
+	/* Ownership of the FP regs */
+	enum {
+		FP_STATE_FREE,
+		FP_STATE_HOST_OWNED,
+		FP_STATE_GUEST_OWNED,
+	} fp_owner;
+
    /*
     * host_debug_state contains the host registers which are
     * saved and restored during world switches.
@@ -540,13 +547,6 @@ struct kvm_vcpu_arch {
    /* Exception Information */
    struct kvm_vcpu_fault_info fault;
-	/* Ownership of the FP regs */
-	enum {
-		FP_STATE_FREE,
-		FP_STATE_HOST_OWNED,
-		FP_STATE_GUEST_OWNED,
-	} fp_state;
-
    /* Configuration flags, set once and for all before the vcpu can run */
    u8 cflags;
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 0d82d9606807..c003d804828b 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -449,12 +449,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
-	/*
-	 * Default value for the FP state, will be overloaded at load
-	 * time if we support FP (pretty likely)
-	 */
-	vcpu->arch.fp_state = FP_STATE_FREE;
-
    /* Set up the timer */
    kvm_timer_vcpu_init(vcpu);
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index f650e46d4bea..4f51293db173 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -84,7 +84,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
     * guest in kvm_arch_vcpu_ctxflush_fp() and override this to
     * FP_STATE_FREE if the flag set.
     */
-	vcpu->arch.fp_state = FP_STATE_HOST_OWNED;
+	*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;
    *host_data_ptr(fpsimd_state) = kern_hyp_va(&current->thread.uw.fpsimd_state);
vcpu_clear_flag(vcpu, HOST_SVE_ENABLED);
@@ -109,7 +109,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
    	 * been saved, this is very unlikely to happen.
    	 */
    	if (read_sysreg_s(SYS_SVCR) & (SVCR_SM_MASK | SVCR_ZA_MASK)) {
-			vcpu->arch.fp_state = FP_STATE_FREE;
+			*host_data_ptr(fp_owner) = FP_STATE_FREE;
    		fpsimd_save_and_flush_cpu_state();
    	}
    }
@@ -125,7 +125,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
 void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)
 {
    if (test_thread_flag(TIF_FOREIGN_FPSTATE))
-		vcpu->arch.fp_state = FP_STATE_FREE;
+		*host_data_ptr(fp_owner) = FP_STATE_FREE;
 }
/*
@@ -141,7 +141,7 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
WARN_ON_ONCE(!irqs_disabled());
-	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) {
+	if (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED) {
/*
    	 * Currently we do not support SME guests so SVCR is
@@ -194,7 +194,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
    	isb();
    }
-	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) {
+	if (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED) {
    	if (vcpu_has_sve(vcpu)) {
    		__vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index f08d6f7b1a3c..e16fa1211e10 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -42,7 +42,7 @@ extern struct kvm_exception_table_entry __stop___kvm_ex_table;
 /* Check whether the FP regs are owned by the guest */
 static inline bool guest_owns_fp_regs(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.fp_state == FP_STATE_GUEST_OWNED;
+	return *host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED;
 }
/* Save the 32-bit only FPSIMD system register state */
@@ -364,7 +364,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
    isb();
/* Write out the host state if it's in the registers */
-	if (vcpu->arch.fp_state == FP_STATE_HOST_OWNED)
+	if (*host_data_ptr(fp_owner) == FP_STATE_HOST_OWNED)
    	__fpsimd_save_state(*host_data_ptr(fpsimd_state));
/* Restore the guest state */
@@ -377,7 +377,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
    if (!(read_sysreg(hcr_el2) & HCR_RW))
    	write_sysreg(__vcpu_sys_reg(vcpu, FPEXC32_EL2), fpexc32_el2);
-	vcpu->arch.fp_state = FP_STATE_GUEST_OWNED;
+	*host_data_ptr(fp_owner) = FP_STATE_GUEST_OWNED;
return true;
 }
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index c5f625dc1f07..26561c562f7a 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -39,7 +39,6 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
    hyp_vcpu->vcpu.arch.cptr_el2	= host_vcpu->arch.cptr_el2;
hyp_vcpu->vcpu.arch.iflags	= host_vcpu->arch.iflags;
-	hyp_vcpu->vcpu.arch.fp_state	= host_vcpu->arch.fp_state;
hyp_vcpu->vcpu.arch.debug_ptr	= kern_hyp_va(host_vcpu->arch.debug_ptr);
@@ -63,7 +62,6 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
    host_vcpu->arch.fault		= hyp_vcpu->vcpu.arch.fault;
host_vcpu->arch.iflags		= hyp_vcpu->vcpu.arch.iflags;
-	host_vcpu->arch.fp_state	= hyp_vcpu->vcpu.arch.fp_state;
host_cpu_if->vgic_hcr		= hyp_cpu_if->vgic_hcr;
    for (i = 0; i < hyp_cpu_if->used_lrs; ++i)
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index bb2c2bc98475..ff502b5e1480 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -346,7 +346,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
__sysreg_restore_state_nvhe(host_ctxt);
-	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED)
+	if (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED)
    	__fpsimd_save_fpexc32(vcpu);
__debug_switch_to_host(vcpu);
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 45b4115c9883..f18cbc9cb680 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -250,7 +250,7 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
sysreg_restore_host_state_vhe(host_ctxt);
-	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED)
+	if (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED)
    	__fpsimd_save_fpexc32(vcpu);
__debug_switch_to_host(vcpu);
-- 
2.33.0


    

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[PATCH OLK-6.6 v3 08/19] KVM: arm64: Exclude FP ownership from kvm_vcpu_arch