linux-kernel - [PATCH 2/4] KVM: arm64: maintain per VM value for CTR

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Message-ID: <20240405120108.11844-3-sebott@redhat.com>
Date: Fri,  5 Apr 2024 14:01:06 +0200
From: Sebastian Ott <sebott@...hat.com>
To: linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Cc: Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	James Morse <james.morse@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>
Subject: [PATCH 2/4] KVM: arm64: maintain per VM value for CTR_EL0

In preparation for CTR_EL0 emulation maintain a per VM for this
register and use it where appropriate.

Signed-off-by: Sebastian Ott <sebott@...hat.com>
---
 arch/arm64/include/asm/kvm_host.h |  1 +
 arch/arm64/kvm/sys_regs.c         | 22 +++++++++++++++-------
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 9e8a496fb284..481216febb46 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -318,6 +318,7 @@ struct kvm_arch {
 
 	/* PMCR_EL0.N value for the guest */
 	u8 pmcr_n;
+	u64 ctr_el0;
 
 	/* Iterator for idreg debugfs */
 	u8	idreg_debugfs_iter;
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 131f5b0ca2b9..4d29b1a0842d 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -215,13 +215,21 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
 /* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
 #define CSSELR_MAX 14
 
+static u64 kvm_get_ctr_el0(struct kvm *kvm)
+{
+	if (kvm->arch.ctr_el0)
+		return kvm->arch.ctr_el0;
+
+	return read_sanitised_ftr_reg(SYS_CTR_EL0);
+}
+
 /*
  * Returns the minimum line size for the selected cache, expressed as
  * Log2(bytes).
  */
-static u8 get_min_cache_line_size(bool icache)
+static u8 get_min_cache_line_size(struct kvm *kvm, bool icache)
 {
-	u64 ctr = read_sanitised_ftr_reg(SYS_CTR_EL0);
+	u64 ctr = kvm_get_ctr_el0(kvm);
 	u8 field;
 
 	if (icache)
@@ -248,7 +256,7 @@ static u32 get_ccsidr(struct kvm_vcpu *vcpu, u32 csselr)
 	if (vcpu->arch.ccsidr)
 		return vcpu->arch.ccsidr[csselr];
 
-	line_size = get_min_cache_line_size(csselr & CSSELR_EL1_InD);
+	line_size = get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD);
 
 	/*
 	 * Fabricate a CCSIDR value as the overriding value does not exist.
@@ -283,7 +291,7 @@ static int set_ccsidr(struct kvm_vcpu *vcpu, u32 csselr, u32 val)
 	u32 i;
 
 	if ((val & CCSIDR_EL1_RES0) ||
-	    line_size < get_min_cache_line_size(csselr & CSSELR_EL1_InD))
+	    line_size < get_min_cache_line_size(vcpu->kvm, csselr & CSSELR_EL1_InD))
 		return -EINVAL;
 
 	if (!ccsidr) {
@@ -1862,7 +1870,7 @@ static bool access_ctr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 	if (p->is_write)
 		return write_to_read_only(vcpu, p, r);
 
-	p->regval = read_sanitised_ftr_reg(SYS_CTR_EL0);
+	p->regval = kvm_get_ctr_el0(vcpu->kvm);
 	return true;
 }
 
@@ -1882,7 +1890,7 @@ static bool access_clidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
  */
 static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 {
-	u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
+	u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm);
 	u64 clidr;
 	u8 loc;
 
@@ -1935,7 +1943,7 @@ static u64 reset_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 static int set_clidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
 		      u64 val)
 {
-	u64 ctr_el0 = read_sanitised_ftr_reg(SYS_CTR_EL0);
+	u64 ctr_el0 = kvm_get_ctr_el0(vcpu->kvm);
 	u64 idc = !CLIDR_LOC(val) || (!CLIDR_LOUIS(val) && !CLIDR_LOUU(val));
 
 	if ((val & CLIDR_EL1_RES0) || (!(ctr_el0 & CTR_EL0_IDC) && idc))
-- 
2.42.0