From 5b0426207998cd1f381b46299907bbcdf8bd240d Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Mon, 19 Feb 2018 14:54:57 +0000 Subject: [PATCH] x86/time: Rework pv_soft_rdtsc() to aid further cleanup MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Having pv_soft_rdtsc() emulate all parts of an rdtscp is awkward, and gets in the way of some intended cleanup. * Drop the rdtscp parameter and always make the caller responsible for ecx updates when appropriate. * Switch the function from being void, and return the main timestamp in the return value. The regs parameter is still needed, but only for the stats collection, once again bringing into question their utility. The parameter can however switch to being const. No functional change. Signed-off-by: Andrew Cooper Reviewed-by: Wei Liu Reviewed-by: Roger Pau Monné Reviewed-by: Jan Beulich --- xen/arch/x86/pv/emul-inv-op.c | 7 ++++++- xen/arch/x86/pv/emul-priv-op.c | 12 ++++++++---- xen/arch/x86/time.c | 8 ++------ xen/include/asm-x86/time.h | 2 +- 4 files changed, 17 insertions(+), 12 deletions(-) diff --git a/xen/arch/x86/pv/emul-inv-op.c b/xen/arch/x86/pv/emul-inv-op.c index f8944170d5..be95a5ff8d 100644 --- a/xen/arch/x86/pv/emul-inv-op.c +++ b/xen/arch/x86/pv/emul-inv-op.c @@ -46,6 +46,7 @@ static int emulate_invalid_rdtscp(struct cpu_user_regs *regs) char opcode[3]; unsigned long eip, rc; struct vcpu *v = current; + const struct domain *currd = v->domain; eip = regs->rip; if ( (rc = copy_from_user(opcode, (char *)eip, sizeof(opcode))) != 0 ) @@ -56,7 +57,11 @@ static int emulate_invalid_rdtscp(struct cpu_user_regs *regs) if ( memcmp(opcode, "\xf\x1\xf9", sizeof(opcode)) ) return 0; eip += sizeof(opcode); - pv_soft_rdtsc(v, regs, 1); + + msr_split(regs, pv_soft_rdtsc(v, regs)); + regs->rcx = (currd->arch.tsc_mode == TSC_MODE_PVRDTSCP + ? currd->arch.incarnation : 0); + pv_emul_instruction_done(regs, eip); return EXCRET_fault_fixed; } diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c index 17aaf97f10..a6bad88488 100644 --- a/xen/arch/x86/pv/emul-priv-op.c +++ b/xen/arch/x86/pv/emul-priv-op.c @@ -1374,10 +1374,14 @@ int pv_emulate_privileged_op(struct cpu_user_regs *regs) case X86EMUL_OKAY: if ( ctxt.tsc & TSC_BASE ) { - if ( ctxt.tsc & TSC_AUX ) - pv_soft_rdtsc(curr, regs, 1); - else if ( currd->arch.vtsc ) - pv_soft_rdtsc(curr, regs, 0); + if ( currd->arch.vtsc || (ctxt.tsc & TSC_AUX) ) + { + msr_split(regs, pv_soft_rdtsc(curr, regs)); + + if ( ctxt.tsc & TSC_AUX ) + regs->rcx = (currd->arch.tsc_mode == TSC_MODE_PVRDTSCP + ? currd->arch.incarnation : 0); + } else msr_split(regs, rdtsc()); } diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c index c90524de9c..1a6fde65dd 100644 --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -2024,7 +2024,7 @@ u64 gtsc_to_gtime(struct domain *d, u64 tsc) return time; } -void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp) +uint64_t pv_soft_rdtsc(const struct vcpu *v, const struct cpu_user_regs *regs) { s_time_t now = get_s_time(); struct domain *d = v->domain; @@ -2045,11 +2045,7 @@ void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp) spin_unlock(&d->arch.vtsc_lock); - msr_split(regs, gtime_to_gtsc(d, now)); - - if ( rdtscp ) - regs->rcx = - (d->arch.tsc_mode == TSC_MODE_PVRDTSCP) ? d->arch.incarnation : 0; + return gtime_to_gtsc(d, now); } bool clocksource_is_tsc(void) diff --git a/xen/include/asm-x86/time.h b/xen/include/asm-x86/time.h index 046302ef19..b3ae832df4 100644 --- a/xen/include/asm-x86/time.h +++ b/xen/include/asm-x86/time.h @@ -56,7 +56,7 @@ uint64_t ns_to_acpi_pm_tick(uint64_t ns); uint64_t tsc_ticks2ns(uint64_t ticks); -void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp); +uint64_t pv_soft_rdtsc(const struct vcpu *v, const struct cpu_user_regs *regs); u64 gtime_to_gtsc(struct domain *d, u64 time); u64 gtsc_to_gtime(struct domain *d, u64 tsc); -- 2.39.5