From 607e8494c42397fb249191904066cace6ac9a880 Mon Sep 17 00:00:00 2001 From: Yang Zhang Date: Mon, 27 Oct 2014 16:40:18 +0100 Subject: [PATCH] vmx: fix save/restore issue with apicv This patch fixes two issues: 1. Interrupts on PIR are lost during save/restore. Syncing the PIR into IRR during save will fix it. 2. EOI exit bitmap doesn't set up correctly after restore. Here we will construct the eoi exit bitmap via (IRR | ISR). Though it may cause unnecessary eoi exit of the interrupts that pending in IRR or ISR during save/restore, each pending interrupt only causes one vmexit. The subsequent interrupts will adjust the eoi exit bitmap correctly. So the performance hurt can be ignored. Signed-off-by: Yang Zhang Signed-off-by: Olaf Hering Reviewed-by: Jan Beulich Reviewed-by: Andrew Cooper --- xen/arch/x86/hvm/vlapic.c | 3 +++ xen/arch/x86/hvm/vmx/vmx.c | 24 ++++++++++++++++++++++++ xen/include/asm-x86/hvm/vlapic.h | 2 ++ 3 files changed, 29 insertions(+) diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c index 2f09713b16..0b7b607de4 100644 --- a/xen/arch/x86/hvm/vlapic.c +++ b/xen/arch/x86/hvm/vlapic.c @@ -1312,6 +1312,9 @@ static int lapic_save_regs(struct domain *d, hvm_domain_context_t *h) for_each_vcpu ( d, v ) { + if ( hvm_funcs.sync_pir_to_irr ) + hvm_funcs.sync_pir_to_irr(v); + s = vcpu_vlapic(v); if ( (rc = hvm_save_entry(LAPIC_REGS, v->vcpu_id, h, s->regs)) != 0 ) break; diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c index 304aeea22d..29aaad4a4a 100644 --- a/xen/arch/x86/hvm/vmx/vmx.c +++ b/xen/arch/x86/hvm/vmx/vmx.c @@ -1584,6 +1584,8 @@ static void vmx_process_isr(int isr, struct vcpu *v) { unsigned long status; u8 old; + unsigned int i; + const struct vlapic *vlapic = vcpu_vlapic(v); if ( isr < 0 ) isr = 0; @@ -1597,6 +1599,28 @@ static void vmx_process_isr(int isr, struct vcpu *v) status |= isr << VMX_GUEST_INTR_STATUS_SVI_OFFSET; __vmwrite(GUEST_INTR_STATUS, status); } + + /* + * Theoretically, only level triggered interrupts can have their + * corresponding bits set in the eoi exit bitmap. That is, the bits + * set in the eoi exit bitmap should also be set in TMR. But a periodic + * timer interrupt does not follow the rule: it is edge triggered, but + * requires its corresponding bit be set in the eoi exit bitmap. So we + * should not construct the eoi exit bitmap based on TMR. + * Here we will construct the eoi exit bitmap via (IRR | ISR). This + * means that EOIs to the interrupts that are set in the IRR or ISR will + * cause VM exits after restoring, regardless of the trigger modes. It + * is acceptable because the subsequent interrupts will set up the eoi + * bitmap correctly. + */ + for ( i = 0x10; i < NR_VECTORS; ++i ) + if ( vlapic_test_vector(i, &vlapic->regs->data[APIC_IRR]) || + vlapic_test_vector(i, &vlapic->regs->data[APIC_ISR]) ) + set_bit(i, v->arch.hvm_vmx.eoi_exit_bitmap); + + for ( i = 0; i < ARRAY_SIZE(v->arch.hvm_vmx.eoi_exit_bitmap); ++i ) + __vmwrite(EOI_EXIT_BITMAP(i), v->arch.hvm_vmx.eoi_exit_bitmap[i]); + vmx_vmcs_exit(v); } diff --git a/xen/include/asm-x86/hvm/vlapic.h b/xen/include/asm-x86/hvm/vlapic.h index 16752b5195..cfe9bdbfab 100644 --- a/xen/include/asm-x86/hvm/vlapic.h +++ b/xen/include/asm-x86/hvm/vlapic.h @@ -61,6 +61,8 @@ #define VEC_POS(v) ((v) % 32) #define REG_POS(v) (((v) / 32) * 0x10) +#define vlapic_test_vector(vec, bitmap) \ + test_bit(VEC_POS(vec), (const uint32_t *)((bitmap) + REG_POS(vec))) #define vlapic_test_and_set_vector(vec, bitmap) \ test_and_set_bit(VEC_POS(vec), (uint32_t *)((bitmap) + REG_POS(vec))) #define vlapic_test_and_clear_vector(vec, bitmap) \ -- 2.39.5