From cbe487fac7fc016dbabbcbe83f11384e1803a56d Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Tue, 3 Aug 2010 10:39:35 +0200 Subject: [PATCH] KVM: PPC: Add mtsrin PV code This is the guest side of the mtsr acceleration. Using this a guest can now call mtsrin with almost no overhead as long as it ensures that it only uses it with (MSR_IR|MSR_DR) == 0. Linux does that, so we're good. Signed-off-by: Alexander Graf --- Documentation/kvm/ppc-pv.txt | 3 ++ arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/kernel/kvm.c | 60 +++++++++++++++++++++++++++++++ arch/powerpc/kernel/kvm_emul.S | 50 ++++++++++++++++++++++++++ 4 files changed, 114 insertions(+) diff --git a/Documentation/kvm/ppc-pv.txt b/Documentation/kvm/ppc-pv.txt index 41ee16d954d..922cf954bd9 100644 --- a/Documentation/kvm/ppc-pv.txt +++ b/Documentation/kvm/ppc-pv.txt @@ -160,6 +160,9 @@ mtmsr rX b mtmsrd rX, 1 b +[Book3S only] +mtsrin rX, rY b + [BookE only] wrteei [0|1] b diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 6d92b4e13eb..7f0d6fcc28a 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -478,6 +478,7 @@ int main(void) DEFINE(KVM_MAGIC_MSR, offsetof(struct kvm_vcpu_arch_shared, msr)); DEFINE(KVM_MAGIC_CRITICAL, offsetof(struct kvm_vcpu_arch_shared, critical)); + DEFINE(KVM_MAGIC_SR, offsetof(struct kvm_vcpu_arch_shared, sr)); #endif #ifdef CONFIG_44x diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c index 226882fe85a..c8bab24ff8a 100644 --- a/arch/powerpc/kernel/kvm.c +++ b/arch/powerpc/kernel/kvm.c @@ -42,6 +42,7 @@ #define KVM_INST_B_MAX 0x01ffffff #define KVM_MASK_RT 0x03e00000 +#define KVM_MASK_RB 0x0000f800 #define KVM_INST_MFMSR 0x7c0000a6 #define KVM_INST_MFSPR_SPRG0 0x7c1042a6 #define KVM_INST_MFSPR_SPRG1 0x7c1142a6 @@ -69,6 +70,8 @@ #define KVM_INST_WRTEEI_0 0x7c000146 #define KVM_INST_WRTEEI_1 0x7c008146 +#define KVM_INST_MTSRIN 0x7c0001e4 + static bool kvm_patching_worked = true; static char kvm_tmp[1024 * 1024]; static int kvm_tmp_index; @@ -264,6 +267,51 @@ static void kvm_patch_ins_wrteei(u32 *inst) #endif +#ifdef CONFIG_PPC_BOOK3S_32 + +extern u32 kvm_emulate_mtsrin_branch_offs; +extern u32 kvm_emulate_mtsrin_reg1_offs; +extern u32 kvm_emulate_mtsrin_reg2_offs; +extern u32 kvm_emulate_mtsrin_orig_ins_offs; +extern u32 kvm_emulate_mtsrin_len; +extern u32 kvm_emulate_mtsrin[]; + +static void kvm_patch_ins_mtsrin(u32 *inst, u32 rt, u32 rb) +{ + u32 *p; + int distance_start; + int distance_end; + ulong next_inst; + + p = kvm_alloc(kvm_emulate_mtsrin_len * 4); + if (!p) + return; + + /* Find out where we are and put everything there */ + distance_start = (ulong)p - (ulong)inst; + next_inst = ((ulong)inst + 4); + distance_end = next_inst - (ulong)&p[kvm_emulate_mtsrin_branch_offs]; + + /* Make sure we only write valid b instructions */ + if (distance_start > KVM_INST_B_MAX) { + kvm_patching_worked = false; + return; + } + + /* Modify the chunk to fit the invocation */ + memcpy(p, kvm_emulate_mtsrin, kvm_emulate_mtsrin_len * 4); + p[kvm_emulate_mtsrin_branch_offs] |= distance_end & KVM_INST_B_MASK; + p[kvm_emulate_mtsrin_reg1_offs] |= (rb << 10); + p[kvm_emulate_mtsrin_reg2_offs] |= rt; + p[kvm_emulate_mtsrin_orig_ins_offs] = *inst; + flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtsrin_len * 4); + + /* Patch the invocation */ + kvm_patch_ins_b(inst, distance_start); +} + +#endif + static void kvm_map_magic_page(void *data) { u32 *features = data; @@ -360,6 +408,18 @@ static void kvm_check_ins(u32 *inst, u32 features) break; } + switch (inst_no_rt & ~KVM_MASK_RB) { +#ifdef CONFIG_PPC_BOOK3S_32 + case KVM_INST_MTSRIN: + if (features & KVM_MAGIC_FEAT_SR) { + u32 inst_rb = _inst & KVM_MASK_RB; + kvm_patch_ins_mtsrin(inst, inst_rt, inst_rb); + } + break; + break; +#endif + } + switch (_inst) { #ifdef CONFIG_BOOKE case KVM_INST_WRTEEI_0: diff --git a/arch/powerpc/kernel/kvm_emul.S b/arch/powerpc/kernel/kvm_emul.S index 3199f65ede2..a6e97e7a55e 100644 --- a/arch/powerpc/kernel/kvm_emul.S +++ b/arch/powerpc/kernel/kvm_emul.S @@ -245,3 +245,53 @@ kvm_emulate_wrteei_ee_offs: .global kvm_emulate_wrteei_len kvm_emulate_wrteei_len: .long (kvm_emulate_wrteei_end - kvm_emulate_wrteei) / 4 + + +.global kvm_emulate_mtsrin +kvm_emulate_mtsrin: + + SCRATCH_SAVE + + LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0) + andi. r31, r31, MSR_DR | MSR_IR + beq kvm_emulate_mtsrin_reg1 + + SCRATCH_RESTORE + +kvm_emulate_mtsrin_orig_ins: + nop + b kvm_emulate_mtsrin_branch + +kvm_emulate_mtsrin_reg1: + /* rX >> 26 */ + rlwinm r30,r0,6,26,29 + +kvm_emulate_mtsrin_reg2: + stw r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30) + + SCRATCH_RESTORE + + /* Go back to caller */ +kvm_emulate_mtsrin_branch: + b . +kvm_emulate_mtsrin_end: + +.global kvm_emulate_mtsrin_branch_offs +kvm_emulate_mtsrin_branch_offs: + .long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4 + +.global kvm_emulate_mtsrin_reg1_offs +kvm_emulate_mtsrin_reg1_offs: + .long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4 + +.global kvm_emulate_mtsrin_reg2_offs +kvm_emulate_mtsrin_reg2_offs: + .long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4 + +.global kvm_emulate_mtsrin_orig_ins_offs +kvm_emulate_mtsrin_orig_ins_offs: + .long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4 + +.global kvm_emulate_mtsrin_len +kvm_emulate_mtsrin_len: + .long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4 -- 2.39.2